CN86104502A - Band steel continuous treatment production line with fired heater - Google Patents

Abstract

The invention relates to band steel continuous treatment production line with fired heater.For heating zone steel under non-oxidation or reduced state, fired heater is equipped with a plurality of reduced form heating burners (reduced form heating burner can form the non-equilibrium zone as reduced zone in flame), each reduced form heating burner is configured to the location status of defined with respect to the band steel, and the distributing style of these reduced forms heating burners on the service line direction be, according to disposing with the determined determining deviation of the relation of burner internal diameter.

Description

Band steel continuous treatment production line with fired heater

The invention relates to band steel continuous treatment production line with fired heater.

The type of heating of band steel continuous treatment production line has indirect heating mode and a naked light type of heating that utilizes the width of cloth to penetrate pipe known to general.Wherein, the naked light type of heating is compared with the indirect heating mode, and have following advantage: heating efficiency is big, and can burn cold-rolled lubricating oil, so can save cleaning equipment etc.Therefore, this type of heating is widely used in pot galvanize service line and electro-magnetic steel plate continuous annealing service line etc.

But the naked light type of heating that the past adopts exists following serious problems: the band steel oxidation is serious, and produces the problem of roller adhesion therefrom.The problem of the naked light type of heating that existed at the past waits in the patent application at the public clear 58-44133 of spy number and special public clear 59-29651 number, has proposed the so-called non-oxidation naked light type of heating that the cold rolled strip continuous heat treatment apparatus is used.This mode characteristics are the risings along with belt steel temperature (the highest 900 ℃), and reduce the coefficient of excess air (＜1,4 → 0.6) etc. of the control area of respectively burning, limit control band steel oxidation in this way, and heat on the limit.

Yet, although this mode is called the non-oxidation mode, be actually the weak oxide mode, when coefficient of excess air less than 1.0 the time, in combustion gas, contain a large amount of CO ₂, H ₂Oxidizing gas such as O are so after the heating, the oxide thickness of raw sheet is just from increasing to 500～1000 less than 50 .Therefore; when this mode is applied to continuous annealing apparatus; have to adopt following method: in the soaking zone of back, heating zone; improve the concentration (hydrogen concentration about about 20%) of hydrogen in the shielding gas; with the reduction-oxidation film; perhaps at the outlet side set handling band of naked light heating zone (strong zone of reduction), carry out the reduction of oxide film etc. with the oxygen (about more than 50%) of high density.

Recently, in order to reduce the production cost of continuous annealing apparatus, equipment trends towards maximizing, but in this equipment, if during with the aforesaid naked light of general formation heating zone, can produce following problem: furnace height increases, make the band steel band that grease be arranged, and be difficult to control furnace pressure.For this reason, have to adopt multistage process furnace more than two sections or two sections.But in the naked light heating zone of this multistage process furnace, owing to form oxide film, the roller in the process furnace can produce the roller adherent phenomenon, and its result can seriously damage the surface quality of band steel.In order to prevent that furnace rolls from producing the roller adherent phenomenon, must take miscellaneous measure, for example open shown in clear 53-54100 number like that the spy, be provided with the insulated chamber that holds furnace rolls, and in this insulated chamber, feed shielding gas etc.Even pair of rollers adopts this protected mode; under the such hot conditions of fired heater; it is very difficult wanting pair of rollers insulated chamber and direct-fired heater suitably to seal; therefore; in order in insulated chamber, to feed enough shielding gas; just must supply with a large amount of shielding gas, this does not have practical value.

The heat treatment mode of continuous hot galvanizing service line is to adopt so-called cracked ammonium pot galvanize (Sendzimir) mode, and this is well-known.This mode, during the cycle, naked light is heated to about 400～450 ℃, is heated to about 750 ℃ in the strongly reducing atmosphere indirect then in continuous annealing.Yet this mode has following problem:

(1) the indirect heating time long, heating efficiency is low.

(2) a large amount of strong reducing gass, i.e. H must be arranged ₂Concentration height (H ₂+ N ₂) gas, for this reason, problem is arranged on safety.

(3) in the time of must carrying out soaking, furnace length will extend.

At the problem of cracked ammonium pot galvanize mode, developed a kind of like this mode, promptly in so-called NOF stove, carry out weak oxide heating after, in weak reduction furnace thereafter, reduce by indirect heating, this mode is widely used at present.Yet this mode also has following problems.

(1) the indirect heating time is long.

(2) in weak oxide-weak reduction process, be with steel can not obtain enough surfactivitys that concerning the coating adaptation, must have.

(3) furnace length increases.

Except that the problems referred to above, continuous heat treatment service line so far also has following problem.

The 1 one problem is; in being provided with the band steel continuous heat treating furnace of fired heater; at first in fired heater; in non-oxidation or reducing atmosphere, will be with steel to be heated to 500～800 ℃; in follow-up special atmosphere oven, will be with thermal treatments such as steel further heats, soaking, chilling then; after being cooled to (in atmosphere, not produce the temperature of oxidation) below 150 ℃, come out of the stove.Malleation about stove domestic demand maintenance+5～15 millimeter water column of above-mentioned special atmosphere oven is to prevent the intrusion of air; In stove, be full of simultaneously shielding gas (3～20%H ₂, all the other are N ₂), so that reduce and anti-oxidation.

Concerning this special atmosphere oven, in atmosphere, draw the sealing mechanism of band steel part after its thermal treatment, generally adopt sealed roller mode and water seal mode, but this dual mode there is following problem respectively.

(1) sealed roller mode

This mode is that a pair of sealed roller is configured in band steel exports side, but just can produce the gap inevitably between the up-down rollers of band steel two side portions and between furnace wall and the roller, therefore, can not seal fully.

Usually, always in this gap, blow out shielding gas in a small amount of stove, invade in the stove to prevent air, but owing to the state of combustion of stove inlet side fired heater changes, when making furnace pressure become negative pressure rapidly, might invading air.

(2) water seal mode

This mode is that the outlet at special atmosphere oven seals with water sealed tank, and the band steel is passed through in this tank.But this mode has water vapor to invade problem in the stove, and to invade the interior problem of stove identical with air for this.

The 2nd problem is; be provided with in the fired heater back on the continuous treatment production line of indirect heater; shielding gas in the indirect heater can flow into fired heater, and then the gas mixture of the combustion exhaust of fired heater and above-mentioned shielding gas is known from experience the inflow preheating oven, the final discharge.In this case,, cause the furnace pressure acute variation, therefore be difficult to management because the change of the flow of each zone of combustion produces the phase mutual interference between each zone of combustion.In addition, will contain the combustion exhaust that does not fire composition and import preheating oven when coming the preheating zone steel, the spent air temperture of preheating oven outlet is lower, is difficult to make do not fire composition perfect combustion.

The present invention is the shortcoming for the band steel continuous treatment production line that overcomes the past, and a kind of improved continuous treatment production line is provided.

The purpose of this invention is to provide a kind of like this continuous treatment production line, promptly be provided with on the band steel continuous treatment production line of fired heater, can be under non-oxidation or reduced state the heating zone steel.

Another object of the present invention provides a kind of like this continuous treatment production line, promptly can heat, be soaked to the condition of high temperature in non-oxidation or following band of reduced state steel.

A further object of the present invention provides a kind of like this continuous heat treatment service line, promptly in fired heater, can be under be everlasting non-oxidation or reduced state the heating zone steel.

Another object of the present invention provides a kind of like this continuous treatment production line, promptly is with steel at least when fired heater comes out, and is the non-oxidation state.

Another object of the present invention provides a kind of like this continuous treatment production line, is the non-oxidation state when promptly being with steel to contact with furnace rolls at least, like this, can prevent the adhesion of roller.

Another object of the present invention provides a kind of like this continuous treatment production line, promptly on the continuous zinc coating service line, can shorten the indirect heating time, obtain necessary enough belt steel surface activity for the coating adaptation, and can shorten the length of whole stove.

Another object of the present invention provides a kind of like this continuous treatment production line, promptly on the continuous heat treatment service line that is provided with fired heater and the controlled atmosphere furnace that is connected on its back, can suitably prevent in the air intrusion controlled atmosphere furnace.

Another object of the present invention provides a kind of like this continuous treatment production line, promptly be provided with successively on the continuous heat treatment service line of preheating oven, fired heater and indirect heater, can prevent that the gas in the stove from flowing in another stove, and can prevent that variation because of furnace inner gas pressure from causing the phase mutual interference between each stove.

Another object of the present invention provides a kind of like this continuous treatment production line, promptly on the continuous treatment production line that is provided with preheating oven, fired heater and indirect heater successively, can utilize combustion exhaust effectively with the preheating of steel.

In order to reach above purpose, continuous treatment production line of the present invention has following structure.

That is, the fired heater of continuous treatment production line disposes a plurality of reduced form heating burners.These heating burners can be formed on the zone that has the burning intermediate product in the flame and do not have free oxygen, promptly non-equilibrium zone.According to the present invention, each reduced form heating burner is configured like this, be that flame and belt steel surface roughly meet at right angles, and in non-equilibrium zone, flame directly contacts with belt steel surface, and these reduced form heating burners are to be configured greater than 0.3 such interval with (burner internal diameter)/(burner spacing) on the service line direction.

The present invention goes for being provided with the continuous treatment production line of the variety of way of fired heater.

In the above-mentioned fired heater that is provided with reduced form heating burner, the band steel heats under non-oxidation or reduced state, and accessible temperature is about 900 ℃, therefore, when handling the band steel under higher temperature, indirect heater is set in the fired heater back.

When continuous treatment production line was the continuous annealing service line, it was constructed as follows:

(1) is provided with fired heater, indirect heater and be cooled to main cool furnace successively, and is provided with planishing mill at the final outlet side of handling band with roll-type.

(2) party upstream of the fired heater of the service line of being mentioned in (1) is provided with preheating oven.

(3) party upstream of the preheating oven of the service line of being mentioned in (1) is provided with cleaning equipment.

(4) be provided with fired heater, indirect heater and successively, and be provided with planishing mill at the final outlet side of handling band based on the cool furnace of liquid cooling.

(5) party upstream of the fired heater of the service line of being mentioned in (4) is provided with preheating oven.

(6) party upstream of the preheating oven of the service line of being mentioned in (5) is provided with cleaning equipment.

Adopt such service line, can carry out continuous annealing effectively, and the band steel is had problems because of oxide film.

When continuous treatment production line is the continuous hot galvanizing service line, at this moment the configuration of each equipment is as follows on the service line, promptly sets gradually the soaking pit-hot galvanizing apparatus of naked light oxidized still-naked light reduction furnace (fired heater of configuration reduced form heating burner)-indirect heating mode.Also can be constructed as follows service line in addition, above-mentioned soaking pit promptly is not set, hot galvanizing apparatus is set in naked light reduction furnace back.

When continuous treatment production line has fired heater and is connected on the controlled atmosphere furnace of its back; can sealing chamber be set in the front of controlled atmosphere furnace outlet side sealed roller; and the device of the furnace pressure that detects this controlled atmosphere furnace can be set and when furnace pressure reduces, sealed gas be blown into device in the above-mentioned sealing chamber; can prevent that like this, just outer gas cut from going in the controlled atmosphere furnace.

When continuous treatment production line is provided with preheating oven, fired heater and indirect heater successively, can between above-mentioned each stove, intermediate chamber be set, and as required, can be between fired heater and preheating oven, secondary combustion chamber is set, make the combustion exhaust perfect combustion in the above-mentioned fired heater, resupply in the preheating oven, like this, can prevent that furnace gas from flowing in another stove, prevent to make to produce the phase mutual interference between each stove, and can utilize combustion exhaust and effectively the band steel is carried out preheating with the variation of furnace inner gas pressure.

On the continuous treatment production line of above-described variety of way, reduced form heating burner can effectively be provided with in the heated perimeter the whole of fired heater.But this burner is compared with general employed non-reduced type burner (dispersion pattern burner), and thermal capacity is little, and when therefore disposing this burner on all effective furnace superintendent, its configuration space is little, if do not use a lot of burners, is to guarantee required heat.

Therefore, reasonably the practice is the above-mentioned reduced form heating of a configuration burner in essential and sufficient scope,, can be configured as follows for this reason.

That is, the distributing style of the 1st kind of reduced form burner that can adopt is that making the band steel is the non-oxidation state when fired heater comes out at least.Its content is, effective furnace superintendent for fired heater, obtain γ % in order to the calculating formula of listing down, on the furnace superintendent part of stove exit side greater than γ %, with above-mentioned spacing ((burner internal diameter/burner spacing) 〉=0.3) configuration reduced form heating burner, the non-reduced type heating of configuration burner on all the other effective furnace superintendent parts. ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the following formula, T _IN: the belt steel temperature (° K) of fired heater inlet

T _OUT: the belt steel temperature (° K) of fired heater outlet

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: at non-reduced type heating burner setting area and reduced form heating burner

The band guiding principle temperature (° K) at the position, boundary of setting area

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕

The distributing style of the 2nd kind of reduced form heating burner that can adopt is, can make the band steel is the non-oxidation state when contacting with furnace rolls at least, like this, can prevent the adhesion of roller, the band steel is come out from fired heater under the non-oxidation state, this mode is exactly each section at fired heater, at least at each section exit region configuration reduced form heating burner that comprises the heating region before outlet side is worn the band roller.

Now accompanying drawing is done a simple declaration:

Fig. 1 and Fig. 2 represent the profile instance of heating burner of the present invention respectively, Fig. 3 and Fig. 4 are illustrated in the service line of the present invention, an example of used heating burner on fired heater, Fig. 3 is a longitudinal diagram, Fig. 4 is the sectional view of the IV-IV line in Fig. 3.

Fig. 5 is that of Fig. 3 and the heating burner shown in Figure 4 scope that forms non-equilibrium zone measures example.

The reduction heat characteristic of Fig. 6 presentation graphs 3 and heating burner shown in Figure 4.

Fig. 7 represents an embodiment of service line of the present invention.

Fig. 8 represents another embodiment of service line of the present invention.

Fig. 9 is illustrated in the generation behavior of oxide film in the fired heater shown in Figure 8 and the variation of belt steel temperature.

Figure 10 represents the sectional drawing of another embodiment of service line of the present invention.

Figure 11 is illustrated in the fired heater shown in Figure 10, the generation behavior of oxide film and the variation of belt steel temperature.

Figure 12～Figure 14 divides expression in addition to adopt the embodiment of continuous annealing service line of the present invention.

Figure 15 represents the cleaning equipment among Figure 14.

Figure 16 is illustrated in the preheating oven of Figure 13 and Figure 14, the relation of the coefficient of excess air of combustion exhaust and non-oxidation preheating ultimate temperature.

Figure 17～Figure 19 divides expression in addition to adopt each embodiment of continuous annealing service line of the present invention.

Figure 20 (A) and (B) respectively expression adopt each embodiment of continuous hot galvanizing service line of the present invention.

Figure 21 adopts the coating service line of Figure 20 (A) and adopts under the coating service line situation of past mode the comparison of the heating curve of each annealing cycle.

Figure 22 represents another embodiment of service line of the present invention.

Figure 23 represents another embodiment of service line of the present invention.

Figure 24 is the partial enlarged drawing of the intermediate chamber among Figure 23.

The characteristic of the heating burner shown in Figure 25～Figure 29 presentation graphs 3 and Fig. 4, Figure 25 represent gas injection hole and air jet hole burner on axially apart from N during for-0.25D, apart from the distance and gas temperature, O of burner outlet ₂The relation of concentration, ionic strength, Figure 26 represent gas injection hole and air jet hole burner on axially apart from N and free O ₂Remaining distance L on burner is axial ₀Relation, when Figure 27 represents apart from N for+0.1D from the distance L of burner outlet and gas temperature, O ₂The relation of concentration and ionic strength, Figure 28 represents the relation apart from N and burner rear wall temperature T b of gas injection hole and air jet hole, Figure 29 represent from the air jet hole to the burner distance L of outlet with to the terminal distance L in non-equilibrium zone _RRelation.

Now detailed explanation is done in invention

The present invention adopts reduced form heating burner under defined terms, this burner can form non-equilibrium zone in flame, promptly have the zone of burning intermediate product and not having free oxygen.Adopt this heating burner, combustion reactions is to finish in flame substantially, at this moment contains CO ₂, H ₂O, N ₂, H ₂, CO etc. zone (being the quasi-equilibrium zone) present oxidisability, the non-equilibrium zone of containing intermediate-ion, atomic group etc. then presents reductibility, and the flame of this burner is almost perpendicular to the band steel, and contacts with the strip at non-equilibrium regional flame, heat like this, can make the band steel not produce oxidation.

Fig. 3 and Fig. 4 are examples of this reduced form heating of expression burner, on the inwall (6) of garden tubular burner block (1), certain intervals along circumferential direction is provided with a plurality of combustion air jet holes (2), simultaneously the centre is provided with fuel gas jet hole (3) in burner, being constructed as follows of combustion air jet hole (2) and fuel gas jet hole (3):

(1) the angle θ that the tangent line in week constitutes in the air direction of the supply of air jet hole (2) and the burner block is less than 60 °.

(2) fuel gas jet hole (3) and air jet hole (2) burner axial apart from N, be set at-0.1D～+ 0.4D (D: the burner internal diameter), when fuel gas jet hole during than the more close burner block outlet side of air jet hole, the N value is (-) value, otherwise is (+) value.

(3) be 0.6D～3D from air jet hole (2) to the distance L of burning spray brick outlet (5).

The heating burner of Gou Chenging like this is owing to be to be 1.0 to use when following at coefficient of excess air, so the non-equilibrium zone of formation in can the certain limit in flame.Promptly, adopt this heating burner, because the rotating fluid of the combustion air that comes out from air jet hole (2) and from the fuel gas of burner central injection, can burn rapidly, therefore in the certain limit of burner outlet outside, formation contains a large amount of burning intermediate products and does not contain the zone of unreacted free oxygen, promptly non-equilibrium zone.Fig. 5 represents the non-equilibrium regional example of measuring with the ion detection detection instrument that this heating burner forms in flame, with the current value height that detection instrument is measured, just ionic strength is big, this means to have a large amount of burning intermediate products.Like this, in the certain limit of burner outlet outside, form non-equilibrium zone, then form in the outside in non-equilibrium district and contain the CO that has finished reaction substantially ₂, H ₂O, N ₂Deng the quasi-equilibrium zone.

Fig. 6 represents the reduction heat characteristic of this heating burner, promptly under the non-oxidation state, heat accessible ultimate temperature (about the ultimate temperature of ordinary steel thin plate), when coefficient of excess air was in 0.85～0.95 scope, the band steel can be heated to about 900 ℃ as can be seen from Figure.

The present invention can also adopt the so-called width of cloth to penetrate the rim of a cup burner as the reduced form burner except that adopting above-mentioned heating burner.This burner has following characteristic: carry out rapidly in order to make combustion reactions, air and fuel gas are mixed in advance, mixed gas is promptly burnt in the hemispherical recesses of burner block, and like this, the internal surface of burner block reaches a high temperature, therefore, at this moment be to penetrate with the width of cloth that to conduct heat serve as to heat mainly, heating object can obtain the very high hot-fluid of temperature at high-temperature area, and, is when burning below 1.0 with this burner at coefficient of excess air, can form non-equilibrium zone in flame.

But, this width of cloth is penetrated burner, and there are the following problems: owing to combustion air and fuel gas taked the mode that is pre-mixed, therefore, can not carry out preheating to combustion air, and because of not carrying out preheating to air, therefore being heated under the non-oxidation state about 750 ℃, can not be applied to be heated to the situation of higher temperature.Say with regard to this point, with heating burner shown in Figure 3 the time, owing to can utilize the air of preheating, therefore the band steel can be heated to about 900 ℃ under the non-oxidation state, simultaneously, owing to utilize preheated air, flame temperature can be improved, therefore penetrate burner with the width of cloth and compare, can more effectively bring into play the reductive action of intermediate reaction resultant.

In the present invention, reduced form heating burner is to be configured with the interval of (burner internal diameter)/(burner spacing) greater than 0.3 on the service line direction.As mentioned above, this burner can heat belt steel surface under non-oxidation or reduced state owing to form non-equilibrium zone in its flame.But according to present inventor's research, if sparsely dispose this heating burner in the service line direction, then owing to there are combustion gases (quasi-equilibrium gas) between burner, the band steel can be oxidized.Therefore, the present inventor comes reductive for the flame by the heating burner and is heated the band steel of the combustion gases oxidation between the burner again, according to the relation of heating burner internal diameter, studied the condition of keeping its reduced state on the whole with the spacing of heating burner on the service line direction.At first, the reduction rate A (T) when available following formula is obtained the band steel and faced non-equilibrium zone in the heating burner flame, and the oxidation rate B (T) of band steel when facing oxidisability combustion gases between the heating burner.The speed of obtaining like this is applicable to that net calorific value is greater than 2000Kcal/Nm ³Combustion gases. $A\left(T\right)={127000e}^{-\left(\frac{6433}{T}\right)}$ (A/ second) $B\left(T\right)={69200e}^{-\left(\frac{6126}{T}\right)}$ (A/ second)

In the formula, T: belt steel temperature (° K)

And, suppose that the internal diameter of heating burner is d, the spacing of heating burner on the service line direction is P, γ=d/P, then for the band steel that utilizes heating burner (being configured at a certain distance on the service line direction) to heat, in order to keep its reduced state, following formula must be set up

γ·A(T)-(I-γ)·B(T)≥0………(1)

In the formula, A (T), B (T) are the functions of temperature, when, separating (1) formula according to temperature function, are shown below, and in 0～1000 ℃ of temperature range, B (T)/(A (T)+B (T)) is roughly 0.3. $\mathrm{\γ}\≥\frac{B\left(T\right)}{A\left(T\right)+B\left(T\right)}\≈0.3$

Fig. 1 and Fig. 2 represent the configuration example of reduced form heating burner of the present invention (a), and Fig. 1 represents interconnected, and Fig. 2 represents configuration arranged side by side.No matter any configuration, reduced form heating burner (a), its burner inner diameter d should be more than 0.3 with the ratio d/p of burner spacing P on the service line direction.

Reduced form heating burner of the present invention is performed such configuration, and promptly its flame is approximately perpendicular to the band steel, and in non-equilibrium zone, flame directly contacts belt steel surface.At fired heater in the past, for example used heating burner in NOF stove etc. can not form the non-equilibrium zone that obvious difference is arranged with other zones.Therefore, when macroscopic flame directly contacted with the band steel, belt steel surface was oxidized significantly.In order to make direct contact zones steel of flame, burner is performed such configuration: the formed flame of burner parallels with the strip width direction.The reduced form of the present invention's employing heats burner in contrast, come the heating zone steel to be provided with in order to utilize on the length direction of burner flame formed non-equilibrium zone, therefore, the flame of burner can be approximately perpendicular to belt steel surface, and directly contacts belt steel surface at its non-equilibrium regional flame.

By the reduced form heating burner that above condition is configured, can be arranged in whole effectively heated perimeters of fired heater, this belt transect steel can heat under non-oxidation or reduced state all the time, so, can obtain certain non-oxidation state.Fig. 7 represents the one example, in the continuous fired heater (8) of a segment type formula, in all effective heated perimeter (promptly in all zones that need heat), has disposed above-mentioned heating burner (a).Heating burner (a) is configured in the both sides of band steel (s) at regular intervals along the length direction of process furnace.

If in whole heating regions of each section of fired heater, all utilize this reduced form heating burner to heat, the band steel is heated under the non-oxidation state all the time, but this burner is compared with the general non-reduced type burner (dispersion pattern burner) that uses, thermal capacity is little, and therefore when whole heating regions of each section disposed this burner, its configuration space was little, that is to say the burner that needs configuration more, otherwise can not guarantee required heat.

For this reason, the present invention is in order to reach the purpose of defined, and just this reduced form of configuration heats burner, configurable non-reduced type burner in all the other scopes in essential and sufficient scope.

At first, in the present invention, be to set with the non-oxidation state of steel " band ", its target is that to be with steel at least be to be in the non-oxidation state when fired heater comes out.

In this case, the basic burner collocation form that is adopted is that only the above-mentioned reduced form of configuration heats burner in the certain limit of fired heater outlet side, and is configured to past non-reduced type heating burner at the rest part of furnace superintendent.Because the inlet side at fired heater has disposed non-reduced type heating burner, therefore can replenish the shortage of heat that causes owing at outlet side configuration reduced form heating burner, and non-reduced type heating burner is at the oxide film of belt steel surface formation, because outlet side has adopted reduced form heating burner and can obtain reduction, the band steel is just sent from fired heater under the non-oxidation state as a result.

Promptly, the a plurality of heating burners of configuration on whole useful lengths of stove, in these heating burners, reduced form heating burner is arranged on the stove exit wing furnace and grows up on the part of γ % (with respect to effective furnace superintendent), and non-reduced type heating burner is arranged on remaining length of stove.γ can obtain with following formula. ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula, T _IN: the belt steel temperature of fired heater ingress (° K)

T _OUT: the belt steel temperature in fired heater exit (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

T ^*: establish in non-reduced type heating burner setting area and reduced form heating burner

Put the belt steel temperature (° K) at the position, boundary in zone

F (T): rate of heating (° K/ second)

〔＝dT/dt〕

More than constituting is the non-equilibrium zone (reduced zone that utilizes heating burner flame, heat burner with reduced form) and quasi-equilibrium zone (oxide regions, with non-reduced type burner) reduction rate A (T) and oxidation rate B (T), and make oxide thickness is zero, decides the configuration scope of reduced form heating burner.

That is, in fired heater, the amount of oxidation of band steel depends on the duration of contact in band steel and above-mentioned two zones.In addition, according to present inventor's research, the available following formula of oxidation rate B (T) in the reduction rate A (T) in above-mentioned non-equilibrium zone and quasi-equilibrium zone is obtained.Each speed of obtaining applicable to net calorific value greater than 2000Kcal/Nm ³Combustion gases. $A\left(T\right)={127000e}^{-\left(\frac{6433}{T}\right)}$ (/second) $B\left(T\right)={69200e}^{-\left(\frac{6126}{T}\right)}$ (/second)

In the formula, T: belt steel temperature (° K)

Therefore, on the furnace superintendent direction, the belt steel temperature that heats the boundary part of burner setting area and reduced form heating burner setting area in non-reduced type is assumed to be T ^*The time, the oxide thickness of fired heater exit band steel can be obtained with following formula. ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}$

In the formula, T _IN: fired heater ingress belt steel temperature (° K)

T _OUT: fired heater exit belt steel temperature (° K)

F (T): rate of heating (° K/ second)

〔＝dT/dt〕

Therefore, with following (1) formula, can obtain oxide thickness and be the belt steel temperature T at zero position, boundary ^*, consider that the band steel is to heat up with certain speed basically in the effective furnace superintendent scope of process furnace, therefore, according to the belt steel temperature T at position, boundary ^*, with following (2) formula can obtain make oxide thickness be zero, with respect to total effectively reduced zone of furnace superintendent, promptly should dispose reduced form heating burner the furnace superintendent zone the ratio γ % that must account for.

………(1) ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

………(2)

The present invention is according to the γ that calculates like this, with respect to total effectively furnace superintendent the furnace length of stove exit side greater than the part of γ % on configuration reduced form heating burner, the non-reduced type heating of configuration burner on all the other furnace superintendents parts.

Fig. 8 represents that in the figure, (7) are preheating ovens by the embodiment of the definite service line of such condition, and (8) are fired heaters, and (9) are indirect heaters, (S) is the band steel.

In addition, in Fig. 8, I refers to give hot stove, and II indicates fiery process furnace, and III refers to heat soaking pit.

Be configured in the heating burner on the total effectively furnace superintendent of fired heater, can be divided into six groups of #1～#6.Then, according to above-mentioned condition, when the reduction heating region must be greater than 24% the time, in #1～#6 heating burner group with respect to total furnace superintendent, #5 and #6 (always being about effectively 30% of furnace superintendent scope) configuration reduced form heating burner, all the other #1～#4 dispose non-reduced type heating burner.Certainly, the not mediocre speech of putting, above-mentioned a plurality of reduced forms heating burners are that method by aforementioned definite spacing is configured.

Fig. 9 is illustrated in an example of the variation of the generation behavior of belt steel surface oxide film in this equipment and belt steel temperature, the oxide film that is generated in the zone (weak oxide heating region) of the non-reduced type heating of configuration burner, be reduced to the oxide thickness of raw sheet in the follow-up zone (reduction heating region) that disposes reduced form heating burner, therefore be with steel to be the non-oxidation state basically and send from process furnace.

In addition, in Fig. 9, I refers to give the oxidation when hot, and II refers to the raw sheet oxide film: 20 , III refer to that (#1～#4), IV refer to reduction heating (#5～#6) in the weak oxide heating.

Secondly, before wearing of each section of fired heater outlet side is with roller, if the band steel is the non-oxidation state, can prevent the roll banding phenomenon because of being with steel oxidation to produce so, its result can make the band steel come out from fired heater under the non-oxidation state.

Therefore, the present invention can set " band steel non-oxidation state " as dbjective state.In this case, with above-mentioned spacing ((burner internal diameter/burner spacing) 〉=0.3), reduced form heating burner is configured in the exit region (comprising the heating region before outlet side is worn the band roller at least) of fired heater.In such formation, for each section that constitutes fired heater, at stove inlet side heating region, owing to disposed the great non-reduced type heating burner of thermal capacitance, can guarantee enough heats, disposed reduced form heating burner at stove exit side heating region simultaneously, can reduce at the formed in its surface oxide film of inlet side heating region for the band steel, therefore being with steel is to send into next section or send into the soaking zone under the non-oxidation state.

Figure 10 represents one embodiment of the present of invention, and this is side that is applicable to the heating of 2 segmentation naked lights.In the figure, (I) expression is the 1st section, and (II) expression is the 2nd section, (10a)～(10d) is to wear the band roller in the stove.In this furnace construction, wear band roller (10b) at each section outlet side and reach (10d) preceding heating region, configuration heating burner group (11), heating burner group (11) they are exactly a plurality of reduced form heating burners (a) that dispose on the service line direction.In addition, the non-reduced type that adopts usually in all the other heating region configurations heats the heating burner group (12) that burner is formed.

In addition, heating burner group shown in Figure 10, just usefulness be the nozzle mixed type, can form short flamed burner.They are performed such configuration: in the quasi-equilibrium zone, flame can directly contact with the strip.

In the present embodiment, at the outlet side of the 1st section (I) and the inlet side of the 2nd section (II), to wear band roller (10b) and (10c) be not subjected to penetrate in order to make, and be provided with outstanding masking shield (13) from the direct width of cloth of direct-fired heater.

In this fired heater, band steel (S) heats with heating burner group (12) at the inlet side and the region intermediate of each section, be subjected to oxidation to a certain degree, but by wearing band roller (10b) at each section outlet side and (10a) precedingly carrying out the heating of reductibility with heating burner group (11), this oxide film is reduced, the band steel under the non-oxidation state by wearing band roller (10b), (10c, (10d), and under the non-oxidation state, send into the indirect heater that is connected on the back from the furnace outlet side.

Figure 11 is illustrated in the thickness of first section (I) oxide film in this fired heater and the variation of belt steel temperature, the oxide film that generates in the zone (weak oxide heating zone) that has disposed non-reduced type heating burner, be provided with the thickness that follow-up reduced form heating burner outlet area (reduction heating zone) is reduced the plate oxide film, so the band steel is sent in follow-up second section (II) under the state of essentially no oxidation.

In addition, in Figure 11, I refers to the oxidation of pre-thermogenesis, and II refers to the oxide film on the raw sheet: 20 .

The present invention can be the continuous treatment production line of the form of ownership of being furnished with fired heater as object, and any form of these continuous treatment production lines all can adopt above-mentioned entire infrastructure.

In the above-mentioned fired heater of being furnished with reduced form heating burner, the band steel can reach about 900 ℃ in the temperature that heats under non-oxidation or the reduced state.Therefore, when be under higher temperature the band steel being heat-treated, as shown in Figure 8, can be at the back continued access indirect heater (9) of fired heater (8).

The present invention is continuous treatment production line during as object, continuous annealing service line and continuous hot galvanizing service line as two kinds of basic forms (not getting rid of other form).

At first the continuous annealing service line with regard to one of above-mentioned basic form describes.

Can enumerate following several form as the example of continuous annealing service line:

(1) dispose fired heater, indirect heater and successively based on the cool furnace of cooling roller, and at the connection line operation line of the discharge end configuration planishing mill of final treatment zone;

(2) before the fired heater of the continuous processing line of above-mentioned (1), the continuous processing line of configuration preheating oven;

(3) before the preheating oven of the continuous processing line of above-mentioned (2), the continuous processing line of configuration cleaning equipment.

In said structure, the band steel heats in reducing atmosphere with reduced form heating burner in fired heater, so deliver in the indirect heater under the non-oxidation state.When heating in fired heater, burning is removed attached to the ROLLING OIL on the belt steel surface.Carry out soaking in follow-up indirect heater in reducing atmosphere, because the band steel is almost being sent into this indirect heater under the non-oxidation state, therefore, furnace atmosphere keeps the weak reducing atmosphere (hydrogen: 3～10%) just enough of non-oxidation state.In follow-up cool furnace, be provided with cooling roller, carry out cooling based on cooling roller.Overaging is set usually in the back of cool furnace handles stove, after the final cooling zone that the band steel is handled the stove back from overaging comes out, carry out smooth with planishing mill.In such equipment, fired heater is set, and in this process furnace, can carry out nonoxidizing heating, its result can control to the hydrogen concentration in the indirect heater (soaking zone) very low, and by cooling roller can will the band steel be chilled to the overaging temperature, therefore, needn't heat again for carrying out the overaging processing.For above-mentioned reasons, continuous annealing furnace of the present invention is compared with continuous annealing furnace in the past, significantly conserve energy.In addition, owing to adopt nonoxidizing heating and carry out the refrigerative mode, can prevent to be with steel oxidation, thereby can not need pickling installation fully with water cooled rolls.And owing to adopt to willing naked light type of heating of thermal load and the easy water cooled rolls mode of adjusting the cooling period, add and select satisfactory material, just can accurately promptly change thermal cycling, so the cycle of continuous annealing just can be freely, that is to say that in fact wide etc. it doesn't matter with furnace temperature, thickness of slab, plate to handle operation.

In addition, on above-mentioned continuous processing line, the front of fired heater is provided with preheating oven, and the band steel by behind the heating by the exhaust gases that is guided into from fired heater, enters fired heater in this preheating oven.When carrying out continuous annealing, because heat-up time is short, the chronergy of heating is little, compare with the batch-type annealing furnace, can set to such an extent that operate under the higher situation in Heating temperature, special carrying in addition on the equipment that has disposed reduction fired heater of the present invention, in order to carry out the short annealing operation, this tendency is stronger, that is, the Heating temperature of setting is higher.Thereby, in such band steel continuous annealing treating processes,, alleviated heating load in fired heater by the band steel is carried out preheating, can carry out suitable high temperature, short annealing.Simultaneously, by preheating, even belt steel surface has oxidation to a certain degree, but can make its reductive fired heater owing to be provided with, therefore, in preheating oven, can carry out 250～500 ℃ high temperature preheating, can will burn attached to the ROLLING OIL on the belt steel surface, combine with in fired heater, removing ROLLING OIL, make the present invention have the good burning performance of deoiling.

In addition, use the naked light type of heating, fast because of rate of heating, to compare with the indirect heating mode, therefore Heating temperature (final Heating temperature) height, correspondingly needs extra energy.But, by preheating oven is set the band steel is carried out preheating, heating gradient is reduced, do not need Heating temperature is brought up to more than the temperature of needs.

In addition, on the continuous processing line of above-mentioned (3), be provided with the belt steel surface cleaning equipment before above-mentioned preheating oven, this cleaning equipment main purpose is to remove attached to the iron powder on the belt steel surface.Through on the cold rolling belt steel surface, adhere to ROLLING OIL and iron powder (rolling bits etc.) usually.ROLLING OIL wherein can be got rid of in fired heater as described above and preheating oven, but iron powder can not remove, so will be deposited in the stove,, holds under the arm between roller and band steel at the stove internal recycle with furnace gas, produces scratch defect on finished product.On this service line, then available above-mentioned cleaning equipment is removed this iron powder.In addition, to contain Si, P, Mn, Ti, when band steel that the Cr equal size is high carries out continuous annealing, these elements generate and are difficult to the reductive oxide film, therefore, for alleviating the oxidation in preheating and naked light heating (heating before the reduction heating) process, can reduce the coefficient of excess of burning with gas.Do like this, in preheating oven and fired heater, characteristic is removed in the burning of the ROLLING OIL of belt steel surface can decrease to some degree.But, adopt above-mentioned cleaning equipment can remedy the deoil reduction of characteristic of this burning, can obtain the effect of appropriate removal ROLLING OIL.

Figure 12 represents the embodiment corresponding to the continuous processing line of above-mentioned (1), begin to be disposed with fired heater (8) from inlet, indirect heater (9), cool furnace (14), stove (15) is handled in overaging, final cool furnace (16) is at the outlet side of final cool furnace (16), by disposing planishing mill (18) behind the outlet kink (17).

The indirect heater (19) that is connected on the fired heater back adopts the type of heating of radiator tube to heat, and is the same with in the past indirect heater basically.But; on this continuous annealing service line; fired heater (8) has reducing power; the band steel is sent into indirect heater (9) under the non-oxidation state; therefore; use the protective atmosphere that does not make the band steel oxidation in this indirect heater, the protective atmosphere of promptly hydrogeneous 3～10% (wishing hydrogeneous 4～6% usually) is just enough.

Configuration a plurality of cooling rollers (19) (normally water cooled rolls) in follow-up cool furnace (14) can be adjusted the temperature of cooling off terminal point by changing this cooling roller (19) with the contact length of band steel (s).

In addition, the working roll of planishing mill (18) with hard chromium roller for well.The most handy patent No. of this roller is that the clear 60-41009 and the patent No. are such roller of introducing in the patent of clear 60-41011.This roller is difficult for producing the scratch that is caused by the strip edge rib, therefore, can suitably prevent to produce defective owing to the roller defective makes belt steel surface, and can make belt steel surface certain rugosity be arranged to keep higher stamp rate.Like this, the band steel of different in width can freely carry out continuous annealing by row.That is to say, with continuous annealing method in the past, for fear of the above-mentioned the sort of detrimentally affect that the band steel is caused by edge tracking and roller defective, the band steel of handling must carry out successively continuously by its width, but by adopting the above-mentioned the sort of abrasive hard chromium roller that do not produce, can not be subjected to above-mentioned constraint, therefore can not consider to carry out the continuous annealing operation with the width of steel.

The embodiment of the continuous processing line that Figure 13 represents above-mentioned (2) is provided with preheating oven (20) (2 segmentation) in the front of fired heater (8).In this preheating oven, introduce the combustion exhaust of from fired heater (8) or indirect heater (9), discharging and come the preheating zone steel.In addition, research according to the present inventor confirms that the coefficient of excess air that uses when the oxidation of band steel is depended on preheating temperature and generated combustion exhaust is adjusted preheating temperature, use is the different combustion exhaust of coefficient of excess air when burning, and the band steel just can almost carry out preheating under the non-oxidizing state.Specifically, as shown in Figure 16, the band steel is when carrying out preheating below 280 ℃, adopting coefficient of excess air is 0.1 combustion exhaust that is generated when above, and the band steel is more than 280 ℃ during preheating, and the employing coefficient of excess air is 0.1 combustion exhaust that is generated when following, like this, although the preheating temperature difference of band steel all is to carry out preheating under the non-oxidation state, but also can carries out preheating expeditiously.

Like this, in preheating oven (20), use the coefficient of excess air of gas with the burning of regulation, just can carry out the non-oxidation preheating, but because oxide film can obtain reduction in the fired heater (8) of back, therefore allow to have in preheating oven (20) oxidation to a certain degree, the result allows preheating temperature to improve about 50 ℃ shown in long and short dash line among Figure 16.Therefore, be about 1.0 also can be preheating to about 400 ℃ at coefficient of excess air, and preheating oven (20) can play the effect that the belt steel surface ROLLING OIL is removed in burning.

Figure 14 represents the embodiment corresponding to the continuous processing line of above-mentioned (3), the front in preheating oven (20), and being provided with to remove iron powder through entry loop (21) is the cleaning equipment (22) of main purpose.This cleaning equipment (22) is mainly used in order to remove iron powder, and is therefore enough with easy equipment.Figure 15 represents an example of this cleaning equipment, and (23) are alkaline bath, and (24) are scrubber (roller brush), (25) be supporting roll, (26) are the warm water spray spout, and (27) are the warm water washing groove, (28) be drying machine, can remove iron powder fully with such cleaning equipment.

In addition, other example of continuous annealing service line also can be enumerated following several form:

(4) dispose fired heater, indirect heater and successively, and handle the continuous processing line that the outlet of being with is provided with planishing mill final based on the cool furnace of cooling liqs;

(5) roam all around the would is provided with the continuous processing line of preheating oven on the fired heater stove of above-mentioned continuous processing line;

(6) roam all around the would is provided with the continuous processing line of cleaning equipment on the preheating oven of the continuous processing line of above-mentioned (5).

In such structure, identical with the continuous processing line of above-mentioned (1)～(3), the band steel heats in non-oxidation and reducing atmosphere in fired heater, then sends in the indirect heater, carries out soaking in reducing atmosphere.Because the band steel is sent into this indirect heater under the state of non-oxidation almost, and by follow-up middle pickling, because of the new oxide film that liquid cooling produces also can be removed, therefore, reducing atmosphere can maintain the week reduction (hydrogen: 2～5%) just enough of non-oxidation state degree.In the cool furnace of back, carry out chilling, will be with steel to be cooled to normal temperature basically, perhaps be cooled to overaging or tempering temperature with hot water etc. based on liquid cooling.Subsequently, the band steel is removed the oxide film that produces because of chilling with middle pickling installation.Then, carry out overaging or temper in overaging processing stove, the band steel that comes out from final cooling zone further carries out smooth with planishing mill.

Such continuous annealing apparatus and since adopt can nonoxidizing heating fired heater, the chilling after the heating soaking is with liquid cooling modes such as hardening liquid or water, therefore, can obtain the good band steel of surface quality.That is to say that when water cooled off after the heating soaking, it is inevitable that belt steel surface generates oxide film.In the past, fired heater and liquid cooling mode combine when using, even the back at fired heater is provided with reduction furnace, residual oxide film also is inevitable, and because further generate oxide film by liquid cooling, even the back then is provided with the equipment that pickling installation etc. is removed oxide film, still residual have an oxide film, therefore guarantees that final product quality is the comparison difficulty.This tendency is remarkable especially on the band of the high Si, the Mn that generate firm oxide film, P, Cr, Ti content.About this point, on continuous processing line of the present invention, because band steel fired heater from reducible heating under the non-oxidation state is sent into indirect heater, cool furnace, therefore it is just passable only to remove the oxide film that produces because of chilling in being connected on the middle pickling installation of cool furnace back, so just can guarantee by pickling oxide film to be removed.In addition, on this continuous processing line, final pickling installation is not set, middle pickling installation is set,, can improve the effect of removing above-mentioned oxide film yet even like this and handle the stokehold in overaging.That is to say,, use strong acid for well, but when use strong acid, generated the deleterious Fe of belt steel surface handling property (OH) in order to improve the effect of removing oxide film with pickling ₂, and, face in the end, when promptly carrying out pickling in the back that stove is handled in overaging, the Fe of generation (OH) ₂Former state remains in belt steel surface, and this has brought variety of issue for the chemical treatment performance of band steel.This point, face is provided with on this continuous processing line of middle pickling installation in overaging processing stokehold, even because of pickling generation back Fe (OH) ₂, but because in the overaging processing stove of back, under reducing atmosphere, reduce, so needn't worry meeting residual Fe (OH) ₂, therefore in fact can carry out pickling with strong acid.In addition, when carrying out high temperature annealing, a spot of carbon is arranged sometimes attached on the belt steel surface with the reductibility naked light.But such carbon also can suitably be removed by middle pickling.

In addition, the continuous processing line of above-mentioned (5) is the same with the continuous processing line of above-mentioned (2), adopt preheating oven to carry out preheating, and the continuous processing line of (6) is the same with the continuous processing line of above-mentioned (3), adopts cleaning equipment to clean.

By above-mentioned preheating, even belt steel surface produces certain oxidation, owing to be provided with the fired heater of reducible oxide film, and pickling installation in the middle of being provided with, therefore, in preheating oven, also can carry out 250～600 ℃ high temperature preheating.

In addition, in fired heater,,, must often keep state of combustion for belt steel surface being reduced heating in the zone that the reduced form burner is set.Therefore, because the difference of belt steel thickness etc., when adjusting the thermal load of process furnace, be necessary to adopt the method that the heating burner in other zone is flame-out, make its effect and preheating oven is set,, can adjust thermal load knifeedge particularly to the thin material process furnace with aid burning.

Figure 17 represents the embodiment corresponding to the continuous processing line of above-mentioned (4), begin to be disposed with fired heater (8) from inlet, indirect heater (9), cool furnace (14), middle pickling installation (29), stove (15) is handled in overaging, and final cool furnace (16) is provided with planishing mill in the exit of final cool furnace (16) after exporting kink.

The indirect heater (9) that is connected on fired heater (8) back adopts the indirect heating mode of radiator tube to heat, and is the same with in the past indirect heater basically.But; on this continuous annealing service line; fired heater (8) has reducing power; the band steel is sent into indirect heater (9) under the non-oxidation state; and because the back has then disposed middle pickling installation; therefore in this soaking zone with the protective atmosphere that does not make the band steel oxidation, promptly use hydrogeneously 2～5%, wish that usually 3～4% protective atmosphere is just passable.

Then in cool furnace (14), will be with steel to immerse in the water and carry out chilling.In water, come out from nozzle, be ejected into the band steel on jet flow, vapor film is removed.

Middle pickling installation (29) is by pickling tank (30), rinse bath (31) and drying machine (32) composition of etc.ing, and for example, the aqueous solution of usefulness HCl5% is 40～60 ℃ of following cleanup acid treatment about 1.5 seconds, cleans with 80 ℃ water then.

Handle in the stove (15) in overaging, band steel (s) carries out overaging processing or temper in weak reducing atmosphere.

In addition, planishing mill (18) preferably uses the same equipment on the continuous processing line with above-mentioned (1).

Figure 18 represents the embodiment corresponding to the continuous processing line of above-mentioned (5), in the front of fired heater (8) preheating oven (20) is set.That introduces in the structure of this preheating oven (20) and the continuous processing line of above-mentioned (2) is the same.

Figure 19 represents the embodiment corresponding to the continuous processing line of above-mentioned (6), and in preheating oven (20) front, being provided with to remove iron powder by entry loop (21) is the cleaning equipment (22) of main purpose.The structure of this cleaning equipment with in the continuous processing line of above-mentioned (3), introduce the same.

In addition,,, can also use tension flattening machine, perhaps can adopt this two kinds of equipment simultaneously except with the planishing mill about the planishing mill in the continuous processing line of above-mentioned (1)～(6).

In the back of cool furnace, the zinc-plated plater of Denging can also be set.

In addition, when the present invention is used for the continuous annealing service line, on this service line, can adopt following thermal cycling, promptly be with steel behind the fired heater internal heating, in the heating of indirect heating type, soaking pit more than the humidity province of regulation was incubated for 5 seconds.The band steel produces nucleus at the heating zone latter half when surpassing recrystallization temperature, crystal grain begins to grow up, and above-mentioned soaking time is to arrive the required shortest time of regulation crystal grain diameter for this crystal grain-growth.

And then, through the heating, soaking the band steel, remain to the temperature of regulation as required after, in the chilling stove with the speed of cooling chilling more than 40 ℃/second.In order to improve the aging performance of finished product, in heating, soaking pit (C) of solid solution, in the overaging stove of chilling back, must make it in the short as far as possible time, to separate out, for realizing this point, make solid solution (C) reach hypersaturated state, above-mentioned speed of cooling is necessary.That is to say that speed of cooling is fast more, the degree of supersaturation of solid solution (C) is high more, and the overaging treatment time is short more, so must limit the slowest speed of cooling.

Then, through a succession of so heat treated band steel, pass through ageing treatment as required, operations such as final cooling are processed into finished product.

Below (1)～(7) be illustrated in have preheating oven-fired heater-indirect heater-gas injection cool furnace-roll-type cool furnace-overaging handles an example of thermal cycling concrete on the continuous annealing service line of stove-final cool furnace.

(1) preheating oven

1200～1400 ℃ of high-temp combustion waste gas with discharging from fired heater are preheating to 250～330 ℃ with the cold belt steel.

(2) fired heater

Be heated to 430～800 ℃ with the cold rolled strip reduction of naked light heating burner after with preheating.

(3) indirect heater

Because in fired heater Heating temperature on be limited to 900 ℃, be heated to higher temperature as needs, heat with indirect heater.After the temperature of band steel reaches the heating upper limit, in weakly reducing atmosphere about 5～120 seconds of soaking.

(4) gas injection cool furnace

The band steel of soaking zone is cooled at a slow speed begin temperature (550～750 ℃) with the quick refrigerative of roll-type cooling zone.

(5) roll-type cool furnace

The band steel is contacted, ℃ to quench the rapid quench to 250 more than 40 ℃/second～400 with water cooled rolls.

(6) stove is handled in overaging

In 400 ℃～150 ℃ zone, keep more than 30 seconds, carry out overaging and handle.

(7) final cool furnace

Band steel after the overaging processing is cooled to come out of the stove in atmosphere below 150 ℃.

With regard to a basic mode in the continuous treatment production line of the present invention, promptly the continuous hot galvanizing service line describes below.

An example of Figure 20 (A) expression continuous hot galvanizing line, (33) are the naked light oxidized stills, and (34) are the naked light reduction furnaces, and (35) are the soaking pits of indirect heating mode, at the back of this soaking pit (35) configuration hot galvanizing apparatus.In above-mentioned naked light reduction furnace (34), reduced form heating burner is set by certain interval.

Other example of Figure 20 (B) expression continuous hot galvanizing service line in this case, is not provided with soaking pit, in the back of fired heater hot galvanizing apparatus is set.This service line is to adopt when carrying out inadequate band steel (s) heating, soaking in naked light oxidized still (33) and naked light reduction furnace (34).

On above-mentioned various zinc-plated service lines, band steel (s) at first carries out the naked light heating in naked light oxidized still (33), meanwhile the rusting of adhering on the belt steel surface is fallen.With such heating means, the band steel is just oxidized.Band steel (s) continues to carry out naked light reduction heating in naked light reduction furnace (34), the oxide film that generates except belt steel surface is hit in reduction.The band steel is by heating in naked light reduction furnace (34), and the oxide film on surface is reduced by force, has realized strong oxidation-strong reduction with the oxidation at naked light oxidized still (33).

After the heating, will carry out pot galvanize in the zinc groove with the continuous processing line shown in steel immersion Figure 20 (B) immediately like this.

In addition, on the service line shown in Figure 20 (A), band steel (s) is heated to the temperature of regulation in naked light oxidized still (33) and naked light reduction furnace (34) after, under the non-oxidation state, send into soaking pit (35).This soaking pit (35) adopts the indirect heating mode.Because the band steel of sending here from the naked light reduction furnace (s) is under the non-oxidation state, therefore do not need reducing gas in theory, just enough with rare gas element.But, in actual production,,, be preferably in and contain a certain amount of hydrogen in the furnace gas in order to remedy this problem because of reasons such as stove gas leakage.But in this case, hydrogen concentration is also just enough below 5%.After the soaking, will be with steel to immerse in the zinc groove and carry out hot dip like this.

Figure 21 expresses the comparison of service line shown in Figure 20 (A) and the various annealing cycle heating curves of service line (sendzimir coating process and NOF method) in the past.On the service line of Figure 20 (A), because of heating with naked light fully, heating efficiency is high more a lot of than mode in the past, therefore, can be heated to the temperature of regulation at short notice, and consequently furnace length can shorten significantly.

In addition, the structure below on the basis of the basic structure of above-mentioned fired heater of the present invention, also can adopting.

(1) in the structure of the service line that is provided with fired heater and special atmosphere oven thereafter; for preventing that atmosphere from entering in the special atmosphere oven; roam all around the would is provided with sealing chamber on special atmosphere oven exit seal roller; and be provided with the device that detects the protective atmosphere furnace pressure and when furnace pressure reduces, sealed gas be blown into device in the above-mentioned sealing chamber.

(2) on the band steel continuous treatment production line that preheating oven, fired heater and indirect heater are arranged in order, in order to prevent that furnace gas is to other stove internal diffusion, and, between above-mentioned each stove, be provided with the intermediate chamber that prevents the furnace gas diffusion for mutual dried the scratching between each stove that prevents to cause owing to the furnace inner gas pressure variation.

(3) on the band steel continuous treatment production line that preheating oven, fired heater and indirect heater are arranged in order, except the purpose of above-mentioned (2), utilize the efficient of combustion exhaust preheating zone steel for raising, on the basis of the structure of above-mentioned (2), between fired heater and preheating oven, secondary combustion chamber is set, supplies with preheating oven after making the combustion exhaust perfect combustion in the above-mentioned direct-fired heater.

Figure 22 is illustrated in an embodiment of the service line of introducing in (1), and this service line is provided with preheating oven (7), fired heater (8) and special atmosphere oven (36) successively from the beginning of band steel inlet.This special atmosphere oven (36) is provided with soaking zone, cooling zone, and can also be provided with overaging as required and handle various processing bands such as band.

Band steel exports place at above-mentioned special atmosphere oven (36) is provided with sealed roller (37), and roam all around the would is provided with sealing chamber (38) on this sealed roller (37).In this sealing chamber (38), be provided with and be blown into the device (39) of sealed gas, and in sealing chamber, be provided with the loadometer (40) of measuring the protective atmosphere furnace pressure.

During with such continuous processing line; band steel (s) is behind preheating oven (7); in fired heater (8); under non-oxidation or reduced state, be heated to 500～800 ℃; in special atmosphere oven (36) thereafter, further be heated to high temperature; and carry out soaking, chilling, overaging processing etc., and be cooled in atmosphere, not have about 150 ℃ of problem of oxidation then, be taken to outside the stove through sealed roller (37) again.

In above-mentioned fired heater (8),, high-temperature combustion gas is supplied with burner by combustion gas (41) and combustion air (42).These combustion gases directly impact on band steel (s), and band steel (s) is heated to after the temperature of regulation, become furnace exhaust, in preheating oven (7), will be with steel to be preheating to 200～450 ℃ after, pass through furnace pressure control sluice (44) and vacuum fan (45) and from chimney, discharge.

For preventing that combustion exhaust from entering in the special atmosphere oven; should dwindle the passage between above-mentioned fired heater (8) and the special atmosphere oven (36), still, unhinderedly pass through for making band steel (s); but need sizable passage (100mm * 2000mm), therefore can not carry out sealing gland here.Thereby the furnace pressure of fired heater (8) changes the furnace pressure that can directly influence special atmosphere oven (36) and changes.At the position of shielding gas (46) from special atmosphere oven (36) inflow fired heater (8), establish pressure warning unit (48), control with furnace pressure control sluice (44), making pressure herein is 5～15mm water column.

It is possible under normal circumstances keeping certain pressure in the stove; but; when the combustion conditions of fired heater (8) changes; when stop working in a zone in for example several zones; the closed action of stove internal control check (44) can not become negative pressure in the special atmosphere oven (36) synchronously sometimes in the short period of time (about 5～10 seconds).In this case, although be provided with sealed roller at band steel (s) from the position that special atmosphere oven (36) comes out, still have big gap herein, air is invaded easily.

In the present invention; in order to prevent atmospheric intrusion; party upstream at sealed roller (37) is provided with sealing chamber (38); between this sealing chamber (38) and special atmosphere oven (36), throttling set is set; detect the reduction (for example than the low 5mm water column of the pressure of setting) of special atmosphere oven (36) pressure with pressure warning unit; at this moment, be blown into sealed gas from the device for blowing that is contained in the sealing chamber (38).This sealed gas can use N separately ₂, also can use and sneak into 3～20%H ₂Gas.

In above-mentioned sealing chamber (38), under normal circumstances also be necessary constantly to be blown into minor N ₂Or other shielding gas, therefore, can on shut-off valve (47), the minor diameter bypass pipe be set, perhaps other pipe arrangement can be connected on the sealing chamber.

The amount of being blown into of sealed gas decides according to the size of throttling set, but only 300～600Nm need be arranged ³The amount of being blown into of/l is just enough, and the time of being blown into is about 10～20 seconds.

Figure 23 represents above-mentioned (2) and the embodiment of the operation line structure of (3).In the figure, I refers to give hot stove, and II indicates fiery process furnace, and III refers to indirect heater.

On this continuous processing line, be disposed with preheating oven (7) in the access device back, fired heater (8), indirect heater (9), gas injection cool furnace (58), back in this cool furnace (58), set gradually with roll-type refrigerative cool furnace, stove and outlet device etc. are handled in overaging.And between preheating oven (7) and fired heater (8), be provided with first intermediate chamber (49a), be provided with second intermediate chamber (49b) in the turning point, top of fired heater (8), between fired heater (8) and indirect heater (9), be provided with the 3rd intermediate chamber (49c).

In Figure 24, describe the structure of intermediate chamber (49a), (49b), (49c) in detail.(49) are intermediate chambers among the figure, (50) be hereinto between the roller of indoor supporting strap steel (S), (51) be middle by vacating closely spaced sealing plate in the middle of band steel (S), the relative configuration, (52) be the sealed roller that clips band steel (S) positioned opposite, (53) pass through band steel (S) labyrinth collar of configuration relatively in the middle of being.Sealing plate (51), sealed roller (52) and labyrinth collar (53) set gradually on the direction away from roller (50).The roll gap of sealed roller (52) can reach several millimeters.The inside of sealed roller (52) can water-cooled, also water-cooled not.When not carrying out water-cooled, use high temperature steel or stupalith.Because labyrinth collar (53) protection sealed roller (52) is not subjected to the thermal radiation from the furnace high-temperature district, so use the refractory materials manufacturing.Sealing plate (51) is as the final usefulness that seals, and not necessarily needs.But because it tightly is located at the back of sealed roller (52), quite near band steel (s), so sealing effectiveness is big.Distance between sealing plate (51) and the labyrinth collar (53) is 50～100mm.In these tightness systems, at first use labyrinth collar (53) tentatively to seal, seal substantially with sealed roller (52), further seal with sealing plate (51).

In Figure 23, the temperature of first intermediate chamber (49a) between preheating oven (7) and the fired heater (8) is also less high, is up to about 300 ℃, does not need pair of rollers to take special sfgd..The gas of first intermediate chamber (49a) reducing gas (H ₂+ N ₂) or combustion exhaust can.But,, need fully sealing for making each stove independently separately.

Example among Figure 23 represents that fired heater (8) constitutes by two sections, is provided with intermediate chamber (49b) between each section.In second intermediate chamber (49b) and the 3rd intermediate chamber (49c), be protection roller the most handy reducing atmosphere, particularly the 3rd intermediate chamber (49c), invade indirect heater (9) for the combustion exhaust that prevents fired heater, must use reducing atmosphere.

Between fired heater (8) and preheating oven (7) secondary combustion chamber (54) is set, it resupplies preheating oven (7) after making the interior combustion exhaust perfect combustion of fired heater (8).As long as the spent air temperture in the exit of fired heater (8) is 800～1200 ℃, more than the unburned gas spontaneous ignition temperature, therefore at secondary combustion chamber (54) lining air supply, unburned gas is burnt at an easy rate.Adopt secondary combustion chamber (54) the unburned gas in the waste gas can not diffused in the atmosphere, can improve spent air temperture, help being with the steel preheating.Outlet at secondary combustion chamber (54) is provided with two passes, and one leads to preheating oven (7), and another leads to relief outlet.By variable valve (55) (56) an amount of waste gas is imported preheating chamber (7).

If when the shielding gas of the shielding gas of the 3rd intermediate chamber (49c) and indirect heater (9) flows into the reduction heating zone of fired heater (8), its reducing power is reduced.That is to say; the temperature of these shielding gas is near the soaking temperature (700～900 ℃) of band steel, and is lower than the temperature (1400～1600 ℃) of combustion gases of reduction heating zone, so the intrusion of shielding gas; the temperature of heating zone of will reducing reduces, and reducing power is significantly reduced.The 2nd secondary combustion chamber (57) is set for this reason, the shielding gas of the 3rd intermediate chamber (49c) and indirect heater (9) is imported the 2nd secondary combustion chamber (57), the problems referred to above can be resolved.

Below the structure of the heating burner among the above-mentioned Fig. 3 of being shown in and Fig. 4 is carried out specific description.

(59) are that inwall (4) at burner block is gone up the outstanding gas jet that is provided with among the figure, in the present embodiment, with certain interval gas injection hole (3) are set at the circumferential direction of this gas jet (59).

In this heating burner, make its air jet hole (2) have certain air feed angle θ, this is to produce eddy flow for the air that makes burning usefulness in burner block, eddy flow is at the inboard negative pressuren zone that forms of burner thus, because the effect combustion gas recirculation of this negative pressure, thereby promote burning, and can form suitable non-equilibrium district.This air feed angle is 60 ° to the maximum, preferably gets 20～40 °, adopts this angle will make the eddy flow of airflow keep stable.

Gas injection hole (3) and air jet hole (2) are N in the distance of burner on axially, as N during in (-) side, the gas temperature height, and the intermediate combustion resultant distribute diametrically very wide, and opposite, free O ₂(unreacted O ₂) then distribute in the axial direction very long.For forming suitable non-equilibrium district, must be with this free O ₂The distance limit axially residual at burner arrives minimum, obtains its ultimate value to be-0.1D.

Figure 25 represent gas injection hole (3) and air jet hole (2) burner axially on apart from N get-during 0.25D, gas temperature, O in the burner axial distance of burner outlet and burner block ₂Concentration and the relation of ionic strength, show according to this figure, N when (-) side, free O ₂Residual in the axial direction distance L ₀Show its existence greatly.

Figure 26 represent gas injection hole and air jet hole burner on axially apart from N and free O ₂Residual distance L on axial line ₀Relation.Show that according to this figure N is during in (-) side and greater than-0.1D, L ₀Sharply become big, therefore, be-0.1D in the ultimate value of (-) side.

Figure 27 represent N get+during 0.1D from the burner axial distance and the O of burner outlet ₂The relation of concentration, ionic strength and gas temperature.

Figure 26 and Figure 27 show, N when (+) side, O ₂Concentration no problem, when 0.5D is above, can form suitable non-equilibrium district from the distance of burner outlet.

N is when (+) side, form suitable non-equilibrium district, still, when N surpasses 0.4D, the mixing effect of air and combustion gas becomes insufficient, that is to say that burner of the present invention injects fuel in the whirl stream of air by position from central division, promote the mixing of air and combustion gas thus, when but N is excessive, can not fully obtain the effect of this promotion blended, the equilibrium area that can not stably form.Therefore, N with+0.4D is the limit.

According to the above, gas injection hole and the air jet hole scope apart from N on burner is axial is-0.1D～0.4D.

In addition, when increasing N, the temperature of burner block inner end wall rises.Figure 28 represents the relation apart from N and burner inner end wall temperature T b.N is+during 0.25D, Tb is 1400 ℃.In general, reach the burner block that such temperature can be used common refractory.When N was 0.4D, the temperature of burner block inner end wall rose to more than 1800 ℃, and in this case, burner block must use the high heat resistance material.

The distance L of outlet (5) and the formation scope in non-equilibrium district have confidential relation from air jet hole (2) to burner block.That is to say that when L surpassed 3D, non-equilibrium district only formed at the position that nestles up burner block outlet back, this is undesirable.In addition, L is when 0.6D is following, and flame is at the flame of the back petalody shape of the outlet of burner block and then, can not obtain suitable non-equilibrium district on axially at burner.Therefore, the scope of L is decided to be 0.6D～3.0D for well.

When heating steel sheet continuously, must maintain a certain distance (usually more than 100mm) between burner block outlet (5) and the steel plate, otherwise the danger of contact burner is arranged when steel plate passes.Therefore, the non-equilibrium district in the flame is preferably in the wide as far as possible scope (comprise apart from the band steel of burner outlet certain distance and pass the position) and forms.Figure 29 represents distance L and exports to terminal (end that burner is tossed about, for example point of the A among Figure 27) distance L in non-equilibrium district from burner _RRelation.According to this figure, when L surpassed 3D, non-equilibrium district only formed in the tight back in burner block exit, forms non-equilibrium district hardly in this front.Along with L diminishes, form the range extension in non-equilibrium district, but L in scope (*) less than 0.6D, radial the tight back flame petalody shape of burner block outlet can not stably form suitable non-equilibrium district at burner on axially.According to the above, the distance L of outlet (5) is preferably in 0.6D～3.0D scope from air jet hole (2) to burner block.

In the structure of above-mentioned heating burner, strong excessively from the air swirl of the jet hole (2) of combustion air ejection, even at the temperature distributing disproportionation that burner directly makes progress in the combustion gas of burner outlet side, the result often is difficult for forming the non-equilibrium district of stable wide region.In this case,, make uniformity of temperature profile, can use following two kinds of structures separately, perhaps it is combined use for relaxing the eddy flow of air.First kind of structure is, the injection direction of gas injection hole (3) and the tangent line of fuel oil atomizer periphery are out of square, and form opposite eddy flow with the airflow that comes out from combustion air jet hole (2) by its gas-flow, and that is to say, form from oppositely going up the eddy flow that conflicts with air swirl.Another kind of structure is, the injection direction of gas injection hole (3) is axial consistent with burner, or favours the axis direction of burner, and has pitch angle (torsion(al)angle) on air jet hole (2), this pitch angle with respect to burner block radially, tilt to the burner opening direction.

In order to enlarge the heating-surface area of burner, can adopt following two kinds of structures.A kind of structure is, on burner block (1) inwall, is to form on the inwall of front opening at position at the combustion air jet hole at least, has the extended corner of burner internal diameter in the hole enlargement of front opening place.Another kind of structure is, in order to form air jet hole (2) easily, in tubular burning brick the eddy channel of using along the combustion air of burner circumferential direction is set, and a plurality of combustion air injections hole is set makes eddy channel and burner internal communication.

Claims (52)

1. the band steel that is provided with fired heater is handled line continuously, it is characterized in that,

Fired heater has several reduced form heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, just flame and belt steel surface are rectangular substantially, and flame can be ejected on the belt steel surface in non-equilibrium zone,

These reduced forms heating burners are being handled on the line direction continuously by following arranged spaced, i.e. the ratio of burner internal diameter and burner spacing is greater than 0.3.

2. it is characterized in that according to the continuous processing line described in the claim (1) that in whole effective heated perimeter of its fired heater, reduced form heating burner all is configured by above-mentioned interval.

3. it is characterized in that according to the continuous processing line described in the claim (1), in the useful length of its fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration; And on remaining useful length, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/sec) $\[={127000e}^{-\left(\frac{6433}{T}\right)}\]$

T ^*: non-reduced type heating burner setting area and reduced form heating burner setting area

The belt steel temperature of territory boundary (° K)

B (T): band steel oxidation speed (/second) $\[=69200e^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕

4. it is characterized in that according to the continuous processing line described in the claim (1), in the outlet side zone of its each section of fired heater, at least be to comprise that outlet side wears in each section outlet side zone of heated perimeter of band roller tight front, dispose reduced form heating burner according to above-mentioned spacing.

5. the band steel that is provided with fired heater is handled line continuously, it is characterized in that it also is provided with indirect heater after fired heater,

Fired heater has several heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each burner is, the surface that make flame and band steel substantially at right angles, and in non-equilibrium zone, flame can be ejected on the surface of band steel,

These reduced form heating burners are disposing by following spacing on the processing line direction continuously, and promptly the burner internal diameter is greater than 0.3 with the ratio of burner spacing.

6. according to the continuous processing line described in the claim (5), it is characterized in that in whole effective heated perimeter of its fired heater that reduced form heating burner is configured by above-mentioned spacing.

7. according to the continuous processing line described in the claim (5), it is characterized in that in the useful length of its fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration; And on remaining useful length of stove, then disposing non-reduced type heating burner, the γ value is calculated by following formula; ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and the setting of reduced form heating burner

The belt steel temperature at area limit place (° K)

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second) (=dT/dt).

8. according to the continuous processing line described in the claim (5), it is characterized in that, at its each section of fired heater, is to comprise that outlet side wears in each section outlet side zone of band roller tight front heated perimeter at least, and reduced form heating burner disposes according to above-mentioned spacing.

9. the band steel that is provided with fired heater is handled line continuously, it is characterized in that it sequentially is provided with: naked light oxidized still, naked light reduction furnace, indirect heater and hot galvanizing apparatus,

The naked light reduction furnace has several reduced form heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, the surface that make flame and band steel substantially at right angles, and flame can be ejected on the belt steel surface in non-equilibrium zone,

These reduced form heating burners are disposing by following spacing on the processing line direction continuously, and promptly the burner internal diameter is greater than 0.3 with the ratio of burner spacing.

10. the continuous processing line described in the claim (9), its special Seeking Truth, in whole effective heated perimeter of its naked light reduction furnace, reduced form heating burner disposes by above-mentioned spacing.

11. the continuous processing line according to described in the claim (9) is characterized in that in the useful length of its fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration; And on remaining useful length, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: naked light reduction furnace strip steel at entry temperature (° K)

T _OUT: naked light reduction furnace outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and the setting of reduced form heating burner

The belt steel temperature (° K) of the boundary in zone

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕。

12. the continuous processing line according to described in the claim (9) is characterized in that, at its each section of naked light reduction furnace, is to comprise that outlet side wears in each section outlet side zone of band roller tight front heated perimeter at least, reduced form heating burner disposes according to above-mentioned spacing.

13. be provided with the continuous processing line of fired heater, it is characterized in that it is provided with the naked light oxidized still, naked light reduction furnace and the hot galvanizing apparatus that is connected therewith,

The naked light reduction furnace has several reduced form heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, the flame and the surface of band steel are met at right angles substantially, and is inferior and can be ejected at flame in the non-equilibrium zone on the surface of band steel,

These reduced form heating burners are being arranged according to following spacing on the processing line direction continuously, and just the burner internal diameter is greater than 0.3 with the ratio of burner spacing.

14. the continuous processing line according to described in the claim (13) is characterized in that, in whole effective heated perimeter of its naked light reduction furnace, reduced form heating burner is configured by above-mentioned spacing.

15. the continuous processing line according to described in the claim (13) is characterized in that in the useful length of its naked light reduction furnace, reduced form heating burner is configured by above-mentioned spacing on greater than the part of γ % in stove exit side length; And on remaining useful length of stove, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: naked light reduction furnace strip steel at entry temperature (° K)

T _OUT: naked light reduction furnace outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and reduced form heating burner are established

Put the belt steel temperature (° K) at area limit place

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕。

16. according to the continuous processing line described in the claim (13), it is characterized in that, at its each section of naked light reduction furnace, be to comprise that outlet side wears in each section outlet side zone of heated perimeter of band roller tight front at least, reduced form heating burner disposes according to above-mentioned spacing.

17. be provided with the continuous processing line of fired heater, it is characterized in that it also is provided with to be attached thereto the special atmosphere oven that connects behind fired heater,

Party upstream at the exit seal roller of this atmosphere furnace is provided with sealing chamber, but also is provided with the device that detects this atmosphere furnace furnace pressure, and the device that is blown into sealed gas when furnace pressure reduces in the sealing chamber.

Fired heater has several reduced form heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, make flame and belt steel surface substantially at right angles, and in its non-equilibrium zone, flame can be ejected on the surface of being with steel,

These reduced forms heating burners are being handled on the line direction continuously by following spacing configuration, and promptly the ratio of burner internal diameter and burner spacing is greater than 0.3.

18. the continuous processing line according to described in the claim (17) is characterized in that, in whole effective heated perimeter of its fired heater, reduced form heating burner is configured by above-mentioned spacing.

19. the continuous processing line according to described in the claim (17) is characterized in that, in the useful length of its fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration; And on remaining useful length of stove, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and reduced form heating burner are established

Put the belt steel temperature (° K) of the boundary in zone

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕

20. the continuous processing according to described in the claim (17) is characterized in that, at its each section of fired heater, is to comprise that outlet side wears in each section outlet side zone of band roller tight front heated perimeter at least, reduced form heating burner disposes according to above-mentioned spacing.

Handle line continuously 21. be provided with the band steel of fired heater, it is characterized in that it sequentially is provided with: preheating oven, fired heater and indirect heater,

Between above-mentioned each stove, be provided with the intermediate chamber that prevents that the furnace gas string is moving,

Fired heater is provided with several reduced form heating burners, and these burners can be formed on has the incendiary intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, the flame and the surface of band steel met at right angles substantially, and should be able to be ejected at flame in the non-equilibrium zone on the surface of band steel,

These reduced form heating burners are disposing by following spacing on the processing line direction continuously, and promptly the burner internal diameter is greater than 0.3 with the ratio of burner spacing.

22. the continuous processing line according to described in the claim (21) is characterized in that, in whole effective heated perimeter of its fired heater, reduced form heating burner disposes by above-mentioned spacing.

23. the continuous processing line according to described in the claim (21) is characterized in that, in the useful length of its fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration; And on remaining useful length, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and the setting of reduced form heating burner

The belt steel temperature (° K) of the boundary in zone

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T) rate of heating (° K/ second)

〔＝dT/dt〕。

24. according to the continuous processing line described in the claim (21), it is characterized in that, at its each section of fired heater, be to comprise that outlet side wears in each section outlet side zone of heated perimeter of band roller tight front at least, reduced form heating burner disposes according to above-mentioned spacing.

Handle line continuously 25. be provided with the band steel of fired heater, it is characterized in that it sequentially is provided with: preheating oven, fired heater and indirect heater,

Between above-mentioned each stove, be provided with the intermediate chamber that prevents that the furnace gas string is moving,

Between above-mentioned fired heater and above-mentioned preheating oven, be provided with secondary combustion chamber, this combustion chamber resupplies in the preheating oven after being the combustion exhaust perfect combustion that makes in the fired heater,

Fired heater has several reduced form heating burners, and these burners can be formed on has the incendiary intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, the surface that make flame and band steel substantially at right angles, and in its non-equilibrium zone, flame can be ejected on the surface of band steel,

These reduced forms heating burners are being handled on the line direction continuously by following spacing configuration, i.e. the ratio of burner internal diameter and burner spacing is greater than 0.3.

26. the continuous processing line according to described in the claim (25) is characterized in that, in whole effective heated perimeter of its fired heater, reduced form heating burner is configured by above-mentioned spacing.

27. the continuous processing line according to described in the claim (25) is characterized in that, in the useful length of its fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration; And on remaining useful length of stove, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and the setting of reduced form heating burner

The belt steel temperature at area limit place (° K)

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕。

28. according to the continuous processing line described in the claim (25), it is characterized in that, at its each section of fired heater, comprise that at least outlet side wears in each section outlet side zone in the heated perimeter of band roller tight front, reduced form heating burner disposes according to above-mentioned spacing.

Handle line continuously 29. be provided with the band steel of fired heater, it is characterized in that it sequentially is provided with: fired heater, indirect heater and be cooled to the cool furnace of main body with roll-type, be provided with planishing mill at the final outlet side of handling the band steel,

Fired heater has several reduced form heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, make flame become vertical substantially with the surface of band steel, and in non-equilibrium zone, flame can be ejected on the surface of being with steel,

These reduced form burners are disposing by following spacing on the processing line direction continuously, and promptly the burner internal diameter is greater than 0.3 with the ratio of burner spacing.

30. the continuous processing line according to described in the claim (29) is characterized in that, in whole effective heated perimeter of fired heater, reduced form heating burner disposes by above-mentioned spacing.

31. according to the continuous processing line described in the claim (29), it is characterized in that, in the useful length of fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration, and on remaining useful length, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and the setting of reduced form heating burner

The belt steel temperature at area limit place (° K)

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕。

32. according to the continuous processing line described in the claim (29), it is characterized in that, at its each section of fired heater, be to comprise that outlet side wears in each section outlet side zone of heated perimeter of band roller tight front at least, reduced form heating burner disposes according to above-mentioned spacing.

Handle line continuously 33. be provided with the band steel of fired heater, it is characterized in that, it sequentially is provided with fired heater, indirect heater and is cooled to the cool furnace of main body with roll-type, is provided with planishing mill at the final outlet side of handling band,

Fired heater has several reduced form heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form burner is, the surface that make flame and band steel substantially at right angles, and in non-equilibrium zone, flame can be ejected on the surface of band steel,

These reduced form heating burners are disposing by following spacing on the processing line direction continuously, and promptly the burner internal diameter is greater than 0.3 with the ratio of burner spacing.

34. handle line continuously, it is characterized in that in whole effective heated perimeter of fired heater, reduced form heating burner disposes by above-mentioned spacing according to the band steel described in the claim (33).

35. handle line continuously according to the band steel described in the claim (33), it is characterized in that, in effective furnace length of fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration, and on remaining useful length of stove, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and reduced form heating burner are established

Put the belt steel temperature (° K) of the boundary in zone

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕。

36. handle line continuously, it is characterized in that at each section of fired heater, comprise that at least outlet side wears in each section outlet side zone of band roller tight front heated perimeter, reduced form heating burner disposes by above-mentioned spacing according to the band steel described in the claim (33).

Handle line continuously 37. be provided with the band steel of fired heater, it is characterized in that this line sequentially is provided with belt steel surface cleaning equipment, preheating oven, fired heater, adds strong stove and be cooled to the cool furnace of main body with roll-type indirectly, at the final outlet side of handling band, be provided with planishing mill

Fired heater has several reduced form heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, the surface that makes flame and band steel substantially at right angles, and in non-equilibrium zone, flame can be ejected on the surface of band steel,

These reduced form heating burners are handled continuously on the line direction at the band steel and are disposed by following spacing, and promptly the burner internal diameter is greater than 0.3 with the ratio of burner spacing.

38., it is characterized in that in whole effective heated perimeter of fired heater that reduced form heating burner disposes by above-mentioned spacing according to the continuous processing line described in the claim (37).

39. handle line continuously according to the described band steel in claim (37) lining, it is characterized in that in the useful length of its fired heater, reduction heating burner stove exit side length greater than the part of γ % on according to above-mentioned spacing configuration; And on remaining useful length of stove, then be the non-reduced type heating of configuration burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and reduced form heating burner are established

Put the belt steel temperature (° K) at area limit place

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕。

40. handle line continuously according to the band steel described in the claim (37), it is characterized in that at its each section of fired heater it being to comprise that outlet side wears in each section outlet side zone of the tight front of band roller heated perimeter at least, reduced form heating burner disposes according to above-mentioned spacing.

Handle line continuously 41. be provided with the band steel of fired heater, it is characterized in that it sequentially is provided with: fired heater, indirect heater, based on the cool furnace of liquid cooling, middle pickling installation and overaging stove, at the final outlet side of handling band, dispose planishing mill

Fired heater has several reduced form heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, make flame and belt steel surface be vertical substantially, and in its non-equilibrium zone, flame can be ejected into the surface of being with steel,

These reduced forms heating burners are being handled on the line direction continuously by following arranged spaced, i.e. the ratio of burner internal diameter and burner spacing is greater than 0.3.

42. handle line continuously, it is characterized in that in whole effective heated perimeter of its fired heater reduced form heating burner is by above-mentioned arranged spaced according to the band steel described in the claim (41).

43. handle line continuously according to the band steel described in the claim (41), it is characterized in that in the useful length of its fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned arranged spaced; And on remaining useful length of stove, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and the setting of reduced form heating burner

The belt steel temperature at area limit place (° K)

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕。

44. handle line continuously according to the band steel described in the claim (41), it is characterized in that at its each section of fired heater it being to comprise that outlet side wears in each section outlet side zone of the tight front of band roller heated perimeter at least, reduced form heating burner disposes by above-mentioned spacing.

Handle line continuously 45. be provided with the band steel of fired heater, it is characterized in that it sequentially is provided with: stove is handled in preheating oven, fired heater, indirect heater, the cool furnace based on liquid cooling, middle pickling installation and overaging, at the final outlet side of handling band, be provided with planishing mill

Fired heater is provided with several prototype heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style that each reduced form heats burner is to make flame rectangular substantially with the surface of band steel, and can be ejected at flame in its non-equilibrium zone on the surface of band steel.

These reduced form heating burners are disposing according to following spacing on the processing line direction continuously, and promptly the burner internal diameter is greater than 0.3 with the ratio of burner spacing.

46. handle line continuously, it is characterized in that in its whole effective heated perimeter of fired heater reduced form heating burner disposes by above-mentioned spacing according to the band steel described in the claim (45).

47. handle line continuously according to the band steel described in the claim (45), it is characterized in that in its useful length of fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration; And on remaining useful length of stove, then dispose non-reduced type heating burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and the setting of reduced form heating burner

The belt steel temperature (° K) of the boundary in zone

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕

48. according to the continuous processing line described in the claim (45), it is characterized in that at its each section of fired heater it being to comprise that outlet side wears in the outlet side zone of the tight front of band roller heated perimeter at least, reduced form heating burner disposes by above-mentioned spacing.

Handle line continuously 49. be provided with the band steel of fired heater, it is characterized in that, this line sequentially is provided with the belt steel surface cleaning equipment, stove is handled in preheating oven, fired heater, indirect heater, the cool furnace based on liquid cooling, middle pickling installation and overaging, at the final outlet side of handling band, be provided with planishing mill

Fired heater is provided with several reduced form heating burners, and these burners can be formed on has the burning intermediate product in the flame, and does not have the non-equilibrium zone of free oxygen,

The distributing style of each reduced form heating burner is, the surface that make flame and band steel substantially at right angles, and in its non-equilibrium zone, flame is wanted can be ejected on the belt steel surface,

These reduced form heating burners are disposing by following spacing on the processing line direction continuously, and promptly the burner internal diameter is greater than 0.3 with the ratio of the spacing of burner.

50., it is characterized in that in its whole effective heated perimeter of fired heater that reduced form heating burner disposes by above-mentioned spacing according to the continuous processing line described in the claim (49).

51. handle line continuously according to the band steel described in the claim (49), it is characterized in that in its useful length of fired heater, reduced form heating burner stove exit side length greater than the part of γ % on by above-mentioned spacing configuration; And on remaining useful length of stove, then be the non-reduced type heating of configuration burner, the γ value is calculated by following formula: ${\∫}_{T^{*}}^{T_{\mathrm{OUT}}}A\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}-{\∫}_{T_{\mathrm{IN}}}^{T^{*}}B\left(T\right)\·\frac{\mathrm{dT}}{F\left(T\right)}=0$

γ＝〔(T _OUT-T ^*)/(T _OUT-T _IN)〕×100

In the formula: T _IN: fired heater strip steel at entry temperature (° K)

T _OUT: fired heater outlet belt steel temperature (° K)

A (T): band steel reduction rate (/second) $[={127000e}^{-\left(\frac{6433}{T}\right)}]$

T ^*: non-reduced type heating burner setting area and the setting of reduced form heating burner

The belt steel temperature at area limit place (° K)

B (T): band steel oxidation speed (/second) $[={69200e}^{-\left(\frac{6126}{T}\right)}]$

F (T): rate of heating (° K/ second)

〔＝dT/dt〕

52. according to the continuous processing line described in the claim (49), it is characterized in that at its each section of fired heater it being to comprise that outlet side wears in each section outlet side zone of the tight front of band roller heated perimeter at least, reduced form heating burner disposes according to above-mentioned spacing.

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