CN105039870A - X80M pipeline steel resistant to low temperature and large in strain and manufacturing method and application of X80M pipeline steel - Google Patents
X80M pipeline steel resistant to low temperature and large in strain and manufacturing method and application of X80M pipeline steel Download PDFInfo
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Abstract
The invention relates to X80M pipeline steel resistant to low temperature and large in strain and a manufacturing method and application of the X80M pipeline steel. The X80M pipeline steel is composed of, by weight, 0.03% to 0.07% of C, 0.15% to 0.35% of Si, 1.50 % to 2.00% of Mn, not larger than 0.009% of P, not larger than 0.002% of S, 0.06% to 0.09% of Nb, 0.015% to 0.020% of Ti, 0.015% to 0.025% of Zr, not larger than 0.30% of Mo, not larger than 0.35% of Cu, not larger than 0.30% of Ni, not larger than 0.30% of Cr and the balance Fe and inevitable impurities. The heating temperature is strictly controlled for implementing low-temperature heating, the grain size is prevented from being increased, and through the reasonable match of a recrystallization deformation temperature section in a rough rolling stage, the rolling reduction of the last pass of rough rolling and the temperature, the austenite grain size is reduced to the maximum degree; and a large accumulated deformation rolling technical measure is adopted in non-recrystallization region deformation in a finish rolling stage, the effect that the phase change is induced through strain is used, a large amount of fine proeutectoid ferrite is generated through low-temperature rolling deformation induction, starting cooling temperature is accurately controlled, and a ferrite and bainite double-phase structure is formed.
Description
Technical field
The invention belongs to structural low alloy steel field, be specifically related to X80M pipe line steel of a kind of low temperature resistant large sstrain and preparation method thereof and application.
Background technology
In recent years along with the continuous growth of energy demand, the resource such as oil, Sweet natural gas of severe cold areas progressively starts exploitation.Carry the pipeline of the oil and gas in this type of area will pass through cold, that landform is unstable region.In this type of region, need to use the think gauge steel pipe that there is superior low-temperature toughness and possess large sstrain performance.For achieving the above object, in the production process of the X80M pipe line steel of low temperature resistant large sstrain think gauge, low-temperature heat when microalloy element solid solution must be ensured, avoid growing up of austenite grain size, the austenite grain refinement effect of steel plate recrystallization district rolling, the low temperature of Unhydrated cement adds up heavy reduction rate rolling generation deformation induced trans-formation and accurate controlled cooling technique after rolling, reaches duplex structure's steel plate of grain refining, realize the feature of low temperature resistant large sstrain with this.
A kind of large wall thickness X80 Low Temperature Station yard steel and manufacture method thereof of good-toughness is described in the Chinese patent application CN103981462A that on 08 13rd, 2014 announce, mainly acicular ferrite structure organized by its steel plate, and the yield tensile ratio of steel plate is higher, do not possess the ability of large sstrain.
A kind of high-intensity high-tenacity-50 DEG C of low-temperature steels and manufacture method thereof is described in Chinese patent application CN101381841A disclosed in 15 days October in 2008.This patent only focuses on controlled rolling and the organizational controls of normalizing heat treatment process, and does not focus on TMCP process crystal grain thinning, controls organization type, thus realizes low-temperature high-toughness.
A kind of method improving toughness of low temperature steel plate is described in Chinese patent application CN101058842A disclosed on 01 04th, 2012, comprise rolling and the heat treatment process of steel plate, this and TMCP process crystal grain thinning, control organization type, realizing low-temperature high-toughness has very big difference.
A kind of method obtaining X80 steel-grade duplex structure large-strain pipeline steel is described in Chinese patent application CN103131833A disclosed on 06 05th, 2013, its processing parameter is that laboratory obtains, and only focus on the enforcement of cooling system, produce from industry spot and the control of whole process production process different.
X80 pipeline steel and the production method thereof of the distortion of a kind of Chinese People's Anti-Japanese Military and Political College is described in Chinese patent application CN103103449A disclosed on 05 15th, 2013, the specification of its not mentioned steel plate, and rough rolling step does not control the lower limit of finishing temperature in texturing temperature in production technique, and intermediate blank is not lowered the temperature after terminating, can not effectively prevent growing up of grain-size.In addition, adopt two benches to cool after document finish rolling, the first stage temperature drop scope of cooling is less, and rate of cooling is higher, relative to air cooling, unstable during production.
A kind of method of producing X80 level large-deformation resistance pipe line steel plate of moderate thickness is described in Chinese patent mandate CN101456034B disclosed in 16 days February in 2011, the thickness of its steel plate is only 12mm, specification is restricted, and Unhydrated cement compression ratio requires more than 5 times, inapplicable to think gauge pipe line steel.
A kind of resistance to deformation X80-100 Pipeline Steel Plate and manufacture method thereof is described in Chinese patent application CN102851587A disclosed on 01 02nd, 2013.This patent is in the grain-size of refinement steel plate, do not control effectively in the passage texturing temperature of rough rolling process, do not carry out the deformation induced trans-formation rolling in finish rolling stage, simultaneously steel plate drop weight test temperature only meets-15 DEG C of environment, can not be applicable to-25 DEG C and low temperature environment lower than this temperature.
The large sstrain X80M dual phase sheet steel that the large soft reduction process of a kind of low temperature is produced is described in Chinese patent application CN103866204A disclosed on 06 18th, 2014, the specification of not mentioned steel plate, and thick steel plates of the present invention comprises below 33mm specification, and the good drop impact toughness that can realize at-25 DEG C of low temperature environments, the present invention focuses in heat-processed, the draught of the control of Heating temperature and soaking temperature and the final pass of recrystallization zone rolling and temperature control the size of fining austenite grains, the finish rolling stage carries out low temperature rolling, carry out deformation induced trans-formation refinement proeutectoid ferrite crystal grain.
Summary of the invention
In order to solve above-mentioned technical problem, the invention provides X80M Pipeline Steel Plate of a kind of low temperature resistant large sstrain and preparation method thereof and application.
In order to solve above technical problem, technical scheme of the present invention is:
An X80M pipe line steel for low temperature resistant large sstrain, is made up of the component of following weight part, C0.03 ~ 0.07%, Si0.15 ~ 0.35%, Mn1.50 ~ 2.00%, P≤0.009%, S≤0.002%, Nb0.06 ~ 0.09%, Ti0.015 ~ 0.020%, Zr0.015 ~ 0.025%, Mo≤0.30%, Cu≤0.35%, Ni≤0.30%, Cr≤0.30%, all the other are Fe and inevitable impurity.
Preferably, described X80M pipe line steel is made up of the component of following weight part, C0.05 ~ 0.06%, Si0.22 ~ 0.31%, Mn1.70 ~ 1.79%, P≤0.009%, S≤0.002%, Nb0.06 ~ 0.07%, Ti0.016 ~ 0.017%, Zr0.019 ~ 0.022%, Mo≤0.15%, Cu≤0.13%, Ni≤0.23%, Cr≤0.22%, all the other are Fe and inevitable impurity.When the proportioning of the various components of pipe line steel is in this numerical range, pipe line steel has good low-temperature flexibility, stress ratio, yield strength, tensile strength, and uniform elongation etc., can adapt to high and cold better, the unstable environment of landform.
A preparation method for the X80M pipe line steel of low temperature resistant large sstrain, comprises the steps:
1) prepare molten iron, and molten iron is carried out desulfurization process;
2) molten iron after desulfurization is passed through smelting, refining, sheet billet continuous casting process successively, the amount of S, P, O, N, H in these three treating processess in the hierarchy of control is less than 130ppm;
3) heating of plate blank, slab heating temperature is 1050 DEG C-1150 DEG C, and soaking zone soaking time is greater than 35min, and total heat-up time is not less than 285min;
4) slab de-scaling, after de-scaling, the surface temperature of slab is 1010-1030 DEG C;
5) slab rough rolling is obtained intermediate blank, again finish rolling is carried out to intermediate blank to after intermediate blank cooling; In rough rolling process, the rolling temperature of recrystallization zone is 960-1010 DEG C, and the temperature of final pass is draft >=12% of 960-980 DEG C, final pass;
6) steel after finish rolling is cooled, before steel plate cooling, steel billet temperature is down to below transformation temperature Ar3 20-100 DEG C;
7) cooled by steel plate, final cooling temperature is 100-250 DEG C, rate of cooling 15-25 DEG C/s;
8) hot straightening is carried out to cooled steel, obtain required steel plate.
Preferably, step 2) in, in described sheet billet continuous casting process, the thickness of the slab of production is 295-305mm, and after sheet billet continuous casting, by continuously cast bloom slow cooling 45-55h, center segregation of casting blank is less than C class 0.5.At utmost reduce segregation to the impact of performance.
Preferred further, in described sheet billet continuous casting process, the thickness of the slab of production is 300mm, after sheet billet continuous casting, by continuously cast bloom slow cooling 50h.
Preferably, step 4) in, after de-scaling, the surface temperature of slab is 1020 DEG C.De-scaling under this condition, can ensure that the iron scale of surface of steel plate is eliminated on clean basis, makes the internal-external temperature difference of steel plate less, and can not cause edge waviness or the middle part arch camber of steel plate, the template of the steel plate obtained is better.
Preferably, step 5) in, the total deformation of rough rolling process is 50-70%, and the thickness of described intermediate blank is 100-150mm.
Preferred further, step 5) in, in rough rolling process, the rolling temperature of recrystallization zone is 1000 DEG C, and total deformation is 57%.
Preferably, to the process of cooling of intermediate blank for utilizing high pressure water, the pressure of high pressure water is 18-22MPa, and the temperature of intermediate blank is down to 800-840 DEG C.This high pressure water can be de-scaling high pressure water, lowers the temperature to intermediate blank with high pressure water, can reduce the grain growth after recrystallize distortion.
Preferred further, be utilize 18-22MPa high pressure water that the temperature of intermediate blank is down to 820 DEG C to the process of cooling of intermediate blank.Intermediate blank is cooled to this temperature, the grain growth after recrystallize distortion can be reduced better.
Preferably, step 5) in, in finishing stands, the rolling temperature of non-recrystallization zone is 680-740 DEG C, rolling 8-16 passage, and the deformation rate of front 2-3 passage is 15%, and accumulation draft is 75-80%.The cumulative deformation adopting the finish rolling stage large and lower rolling temperature, realize deformation induced trans-formation, produce tiny proeutectoid ferrite, refinement proeutectoid ferrite grain-size.
Preferably, step 6) in, after finish rolling terminates, steel plate is carried out air cooling, make the temperature of steel plate lower than transformation temperature Ar370 DEG C.Air cooling step accurately controls out cold temperature, realizes the rational proportion of steel plate ferrite and bainite duplex structure.
Preferably, step 7) in, cooling step adopts MULPIC (multi-functional discontinuous cooling system), and final cooling temperature is 100-250 DEG C, and rate of cooling is 15-25 DEG C/s.This device adopts water convexity and edge part shading cooling technology to ensure that the homogeneity of cooling, cools fast, effectively achieves large sstrain ability and high block hammer performance.
Preferred further, the final cooling temperature of described cooling is 240 DEG C, and rate of cooling is 20 DEG C/s.Under this final cooling temperature and speed of cooling, adaptability to changes and the block hammer performance of steel plate are best.
The application of described X80M pipe line steel in severe cold areas transfer oil, Sweet natural gas.
In its Composition Design, the effect of each element is as follows:
Carbon: along with carbon content increases, the intensity of steel increases and toughness, welding property reduce.But due to reaching its maturity of cooling controlling and rolling controlling process and micro-alloying technology, simultaneously for improving the performance of welded heat affecting zone (HAZ), carbon content in steel reduces gradually, for promoting the low-temperature flexibility of think gauge pipe line steel further, carbon content need be reduced to less than 0.07%.
Silicon: reductor conventional in steel, and there is very strong solution strengthening ability, the deterioration of plasticity and toughness can't be caused in certain scope.
Manganese: being most common alloys element in steel, is conventional reductor and sweetening agent.Mn can significantly improve the hardening capacity of steel, also can improve the toughness of tissue, but will damage plasticity and toughness and welding property during content height when certain content.Mn has solution strengthening effect, also can reduce γ-α transformation temperature, and then fining ferrite grains keep Polygons; Mn also can improve toughness, reduce ductile-brittle transition temperature.
Niobium: Nb can postpone austenite recrystallization, reduce transformation temperature, is obtained the performance of requirement by mechanism such as solution strengthening, phase transformation strengthening, precipitation strengths.The Nb be solid-solubilized in steel can suppress austenite recrystallization and grain growth, contribute to producing tiny ferrite crystal grain, and Nb element and C, atom N have extremely strong avidity, easy formation small and dispersed Nb (C, N), crystal boundary migration can be stoped, improve grain growth temperature, thus reach thinning effect.
Titanium: in austenite, can suppress growing up of austenite crystal, but time more than 1400 DEG C, TiN particle starts alligatoring or dissolving by disperse, tiny TiN particle, and its effect starts to lose.Ti and N has very strong avidity, and in molten steel, Ti just defines TiN with N, does not substantially change intensity when the add-on of Ti is below 0.025%.Ti can improve the low-temperature flexibility of matrix metal and welded heat affecting zone simultaneously, the TiN formed can effective fixed nitrogen, when Al content is lower (being less than about 0.005%), Ti can form a kind of nitride, refinement heat affected zone microstructure, Ti content general control, below 0.02%, too much can cause the alligatoring of the nitride of Ti, unfavorable to low-temperature flexibility.
Zirconium: Zr is carbide in steel, add a small amount of zirconium have degassed, purification and Grain refinement, be conducive to the low-temperature performance of steel.
Chromium: the hardening capacity that can improve steel, has the effect of precipitation strength, improves armor plate strength hardness.Erosion resistance and anti-hydrogen induced cracking ability can be improved simultaneously, and the abrasion resistance properties of steel can be improved.
Nickel: nickel is complete solid solution element in steel, has the effect obviously reducing ductile-brittle transition temperature.Ni and Fe is present in α and γ phase with the form of dissolving each other, and by its adsorption fining ferrite grains in crystal grain, improves the impelling strength of steel.But Ni expands austenitic area element simultaneously, reduce austenitic transition temperature, thus affect the velocity of diffusion of carbon and alloying element, stop austenite to perlitic transformation, reduce the critical cooling velocity of steel, the hardening capacity of steel can be improved, easily make in steel, to occur bainite and martensite, Ni and Mn, Cr with the use of time can significantly improve hardening capacity.
Copper: be dissolved in matrix and will play solid solution strengthening effect, but too high levels will damage toughness and weldability.Cu also can improve the erosion resistance of steel.But easily there is the danger of embrittlement containing Cu steel when hot rolling, need appropriate Ni to eliminate its harm.
Molybdenum: containing in molybdenum steel, along with the increase of the massfraction of molybdenum, the diffusion activation energy of carbon in austenite increases, thus Carbon diffusion coefficient is reduced.Meanwhile, molybdenum can reduce the diffusibility of carbide forming element as Nb etc., thus hinders the formation of carbide, postpones the precipitation process of carbide.Therefore, containing in molybdenum steel, Mo hinders proeutectoid ferrite growth process strongly, improves the obdurability of steel plate.
Although the component of some pipe line steel is with the component of pipe line steel of the present invention, some is overlapping, and the content of these overlapping components is also overlapping, but these components are all some custom requirements of pipe line steel, but the selection of some component in the present invention and the selection of content, all be different from conventional selection, although there will be two documents all cover whole component of the present invention, but the complete overlapping documents of content do not had with component of the present invention and component, list above what these components of the present invention were concrete act on, except the effect that these are basic, these components are passing through smelting, refining, continuous casting, in the processes such as rolling, obtain specific resistance structure, synergy can be produced between each component, as the Zr in the present invention, the content of zirconium is comparatively large, and can make full use of the advantage that it can improve the low-temperature performance of steel, zirconium can fix C and N in steel, improves the transition temperature of proeutectoid ferrite, and ferrite transformation is easy to occur.Zirconium and sulphur can be combined to sulfuration zirconium, reduce fragility.The synergy of the nickel, copper, molybdenum etc. of zirconium and reasonable component concentration, can significantly improve the low-temperature flexibility of pipe line steel of the present invention.Pipe line steel of the present invention is made still to have good cracking resistance toughness and good intensity under cryogenic.
By preparation method of the present invention, control the component proportion obtaining pipe line steel of the present invention, synergy between the internal organizational structure of the pipe line steel obtained and each component is all special, as the selection of Heating temperature in preparation process, the selection of the parameter of finish rolling and rough rolling process, the selection of cooling step and speed of cooling all can affect weave construction and the structure properties of pipe line steel, the internal organizational structure of pipe line steel, synergy between the effect of component and the component excellent low-temperature flexibility that jointly made pipe line steel possess and possess large sstrain performance, and the thickness of the steel plate prepared in production process is larger, the oil of severe cold areas can be met completely, the conveying task of Sweet natural gas etc.
In addition, due to the huge number of element, except conventional element, the element added in different patent is different, so, in numerous elements, select this several element of the present invention, and obtain the proportioning of this several element, the performance of the steel obtained is met the demands, select the process of an inherently great many of experiments, because also refer to, between different element, have synergy above, can not only carry out adding or reducing according to the character of element.And because preparation process also can affect the performance of steel pipe, the various parameter of preparation method and pipe line steel component need on the basis of lot of experiments, could finally determine by constantly adjusting, so, the component of pipe line steel of the present invention, the proportioning between component and the preparation method of pipe line steel are non-obvious.
Beneficial effect of the present invention is:
1, adopt pipe line steel production technique of the present invention, produce the X80M pipe line steel of below 33mm, there is the feature of low temperature resistant, large sstrain ability and think gauge, improve the security of pipeline, be applicable to polar region buried pipeline engineering.
2, the present invention with the addition of alloying element zirconium.Zirconium has the effect of deoxidation, purification and crystal grain thinning in steel, can improve the low-temperature flexibility of steel.Zirconium and nickel element compound, improve the low-temperature flexibility of steel effectively.
3, the present invention is by strictly controlling Heating temperature, and growing up of austenite crystal is avoided in low-temperature heat, and the recrystallize texturing temperature of rough rolling step is interval, the draught of last passage of roughing and the rational Match of temperature, farthest fining austenite grains size; After the distortion of roughing recrystallize terminates, utilize high pressure water to lower the temperature to intermediate blank, to reduce growing up of austenite grain size simultaneously.
4, the Unhydrated cement distortion in finish rolling stage adopts the technique means of large cumulative deformation rolling, improves the flattening degree of austenite crystal, increase phase transformation nucleation site while distortion is penetrated into steel plate heart portion, thus the grain-size of steel plate after refinement phase transformation.Adopt low temperature rolling simultaneously, make full use of the effect of strain-induced transformation, low temperature rolling deformation inductdion produces proeutectoid ferrite tiny in a large number, the grain-size of refinement proeutectoid ferrite, distortion is infiltrated into steel plate center, increase the homogeneity of structure on full thickness direction, improve the low-temperature flexibility of steel plate.
5, the present invention adopts and accurately controls to open cold temperature, realizes the rational proportion of steel plate ferrite and bainite duplex structure, then cools fast, effectively achieve large sstrain ability and high block hammer performance.
6, preparation method of the present invention adopts cooling step to adopt MULPIC (multi-functional discontinuous cooling system), adopts water Crown control and edge part shading cooling technology to ensure that the homogeneity of cooling, achieve the good control of template.
Accompanying drawing explanation
Fig. 1 is process flow sheet of the present invention;
Fig. 2 is the thickness direction surface metallurgical structure figure of 33mm specification X80M steel plate of the present invention;
Fig. 3 is the metallurgical structure figure at thickness direction 1/4 place of 33mm specification X80M steel plate of the present invention;
Fig. 4 is the metallurgical structure figure at thickness direction 1/2 place of 33mm specification X80M steel plate of the present invention;
Fig. 5 is the thickness direction surface metallurgical structure figure of 26.4mm specification X80M steel plate of the present invention;
Fig. 6 is the metallurgical structure figure at thickness direction 1/4 place of 26.4mm specification X80M steel plate of the present invention;
Fig. 7 is the metallurgical structure figure at thickness direction 1/2 place of 26.4mm specification X80M steel plate of the present invention.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is further described.
Embodiment 1
The present embodiment is that the concrete composition of 33mmX80M is as shown in table 1.
The preparation method following (being prepared by the technical process shown in Fig. 1) of a kind of low temperature large sstrain think gauge X80 Pipeline Steel Plate of the present embodiment:
(1) smelting and continuous casting process: adopt Clean Steel to smelt mode, on the basis of ultralow P, S, control five large harmful element total amounts, namely these five kinds of element sums of control S, P, O, N, H are less than 130ppm, ensure purity, the homogeneity of steel.In sheet billet continuous casting process, adopt dynamic soft reduction technology, center segregation of casting blank reaches C class 0.5, and slab thickness is 300mm.
Table 133mmX80M chemical composition (%)
(2) heating of plate blank: in the heating process of slab, slab heating temperature 1140 DEG C.
(3) thick de-scaling: the board briquette controlling thick de-scaling step is 1025 DEG C.
(4) roughing: the temperature of recrystallization zone controlled rolling is 1005 DEG C, the lower limit 975 DEG C that last passage is meeting deformation temperature range carries out, and ensures effective combination of draft >=15% and texturing temperature.After steel plate recrystallization rolling, grain-size is grown up not too much.Workpiece thickness 140mm, accumulative draft 53%;
(5) intermediate blank cooling: utilize roughing mill frame high pressure descaling water to cool intermediate blank, cooling termination temperature 820 DEG C.
(6) finish rolling: it is 736 DEG C that Unhydrated cement controls finish rolling open rolling surface temperature, finishing temperature 695 DEG C, rolling 16 passage.In this stage rolling, adopt large cumulative deformation, deformation induced trans-formation occurs, refinement proeutectoid ferrite crystal grain.Control 2-3 pass deformation rate is 15% simultaneously, improves distortion rate of permeation.Accumulation draft 76.4%.
(7) air cooling: after finish rolling terminates, carries out air cooling cooling to steel plate, is down to below Ar3 transformation temperature 70 DEG C.
(8) cool: adopt MULPIC cooling apparatus to cool fast, final cooling temperature 240 DEG C, speed of cooling 15 DEG C/s.
(9) hot straightening: adopt large straightening force at utmost to discharge stress in steel plate.
Adopt the steel plate of above explained hereafter, final surface, 1/4,1/2 organize as shown in Figure 2, Figure 3 and Figure 4, visible, the ferritic grain-size of pipe line steel prepared by this embodiment is less, and homogeneity of structure is good.The mechanical property of steel plate as shown in table 6 and table 7.
Embodiment 2
The present embodiment is that the specific chemical composition of 27mmX80M is as shown in table 2.
The preparation method of a kind of low temperature large sstrain think gauge X80 Pipeline Steel Plate of the present embodiment is as follows:
(1) smelting and continuous casting: adopt Clean Steel to smelt mode, on the basis of ultralow P, S, control five large harmful element total amounts, namely these five kinds of element sums of control S, P, O, N, H are less than 130ppm, ensure purity, the homogeneity of steel.The main chemical compositions of steel is as shown in table 2, and in sheet billet continuous casting process, adopt dynamic soft reduction technology, slab quality reaches C class 0.5, and slab thickness is 300mm.
Table 227mmX80M chemical composition
| C | Si | Mn | P | S | Ti | Nb | Zr | Cr | Ni | Cu | Al | H | 0 | N |
| 0.05 | 0.26 | 1.70 | 0.008 | 0.002 | 0.017 | 0.065 | 0.019 | 0.22 | 0.10 | 0.12 | 0.029 | 0.0003 | 0.0011 | 0.0028 |
(2) heat: in the heating process of slab, slab heating temperature 1130 DEG C.
(3) thick de-scaling: the board briquette controlling thick de-scaling step is 1025 DEG C.
(4) roughing: the temperature of recrystallization zone controlled rolling is 1000 DEG C, the lower limit 970 DEG C that last passage is meeting deformation temperature range carries out, and ensures effective combination of draft >=15% and texturing temperature, and after distortion, grain-size is grown up not too much.Workpiece thickness 120mm, accumulative draft 60%.
(5) intermediate blank cooling: utilize roughing mill frame high pressure descaling water to cool intermediate blank, cooling termination temperature 825 DEG C.
(6) finish rolling: the surface temperature range of Unhydrated cement controlled rolling is 735 DEG C, stops rolling temperature 695 DEG C, rolling 12-16 passage.In this stage rolling, adopt finish rolling stage large cumulative deformation, make steel plate generation deformation induced trans-formation, the grain-size of steel plate after the grain-size of refinement proeutectoid ferrite and refinement phase transformation, accumulation draft 77.5%.
(7) air cooling: after finish rolling terminates, carries out air cooling cooling to steel plate, is down to below Ar3 transformation temperature 65 DEG C.
(8) cool: adopt MULPIC to cool fast, final cooling temperature 235 DEG C, speed of cooling 21 DEG C/s.
(9) hot straightening: adopt large straightening force at utmost to discharge stress in steel plate.
By the steel plate of above explained hereafter mechanical property as shown in table 6 and table 7.
Embodiment 3
The present embodiment is that the specific chemical composition of 26.4mmX80 is as shown in table 3.
The preparation method of a kind of low temperature large sstrain think gauge X80 Pipeline Steel Plate of the present embodiment is as follows:
(1) smelting and continuous casting: adopt Clean Steel to smelt mode, on the basis of ultralow P, S, control five large harmful element total amounts, namely these five kinds of element sums of control S, P, O, N, H are less than 130ppm, ensure purity, the homogeneity of steel.The main chemical compositions of steel is as shown in table 3: in sheet billet continuous casting process, and adopt dynamic soft reduction technology, slab quality reaches C class 0.5, and slab thickness is 300mm.
Table 326.4mmX80 chemical composition
| C | Si | Mn | P | S | Ti | Nb | Zr | Cr | Ni | Cu | Al | H | 0 | N |
| 0.06 | 0.24 | 1.73 | 0.008 | 0.002 | 0.016 | 0.065 | 0.021 | 0.22 | 0.10 | 0.11 | 0.032 | 0.0001 | 0.0013 | 0.0024 |
(2) heat: in the heating process of slab, slab heating temperature 1125 DEG C.
(3) thick de-scaling: the board briquette controlling thick de-scaling step is 1022 DEG C.
(4) roughing: the temperature of recrystallization zone controlled rolling is 1000 DEG C, the lower limit 970 DEG C that last passage is meeting deformation temperature range carries out, and ensures effective combination of draft >=15% and texturing temperature, and after distortion, grain-size is grown up not too much.Workpiece thickness 120mm.Accumulative draft 60%;
(5) intermediate blank cooling: utilize roughing mill frame high pressure descaling water to cool intermediate blank, cooling termination temperature 810 DEG C.
(6) finish rolling: the surface temperature range of Unhydrated cement controlled rolling is 737 DEG C, stops rolling temperature 702 DEG C, rolling 12-16 passage.In this stage rolling, the cumulative deformation adopting the finish rolling stage large and low temperature finish to gauge, make steel plate generation deformation induced trans-formation, produce tiny proeutectoid ferrite, the grain-size of steel plate after the phase transformation of refinement simultaneously.Control 2-3 pass deformation rate is 15% simultaneously, improves distortion rate of permeation.
(7) air cooling: after finish rolling terminates, carries out air cooling cooling to steel plate, is down to below Ar3 transformation temperature 55 DEG C.
(8) cool: adopt MULPIC to cool fast, final cooling temperature 240 DEG C, speed of cooling 21 DEG C/s.
(9) hot straightening: adopt large straightening force at utmost to discharge stress in steel plate.
By the final surface, 1/4 of the steel plate of above explained hereafter, the tissue of 1/2 is as shown in Fig. 5, Fig. 6 and Fig. 7, visible, and the ferritic grain-size of pipe line steel prepared by this embodiment is less, and homogeneity of structure is good.The mechanical property of steel plate as shown in table 6 and table 7.
Embodiment 4
The present embodiment be 33mmX80 specific chemical composition as shown in table 4.
The preparation method of a kind of low temperature large sstrain think gauge X80 Pipeline Steel Plate of the present embodiment is as follows:
(1) smelting and continuous casting: adopt Clean Steel to smelt mode, on the basis of ultralow P, S, control five large harmful element total amounts, namely these five kinds of element sums of control S, P, O, N, H are less than 130ppm, ensure purity, the homogeneity of steel.The primary chemical of steel is as shown in table 5: in sheet billet continuous casting process, and adopt dynamic soft reduction technology, center segregation of casting blank reaches C class 1.0, and slab thickness is 300mm.
Table 433mmX80 chemical composition
(2) heating of plate blank: in the heating process of slab, slab heating temperature 1130 DEG C.
(3) thick de-scaling: the board briquette controlling thick de-scaling step is 1020 DEG C.
(4) roughing: the temperature range of recrystallization zone controlled rolling is 1005 DEG C, the lower limit 970 DEG C that last passage is meeting deformation temperature range carries out, and ensures effective combination of draft >=15% and texturing temperature.After steel plate recrystallization rolling, grain-size is grown up not too much.Workpiece thickness 145mm, accumulative draft 51.7%;
(5) intermediate blank cooling: utilize roughing mill frame high pressure descaling water to cool intermediate blank, cooling termination temperature 810 DEG C.
(6) finish rolling: the surface temperature range of Unhydrated cement controlled rolling is 735 DEG C, stops rolling temperature 695 DEG C, rolling 12-16 passage.In this stage rolling, adopt the cumulative deformation that the finish rolling stage is large, improve austenitic flattening degree, deformation induced trans-formation occurs and produces tiny proeutectoid ferrite, the grain-size of steel plate after the phase transformation of refinement simultaneously.Control 2-3 pass deformation rate is 15% simultaneously, improves distortion rate of permeation.Accumulation draft 77.2%.
(7) air cooling: after finish rolling terminates, carries out air cooling cooling to steel plate, is down to below Ar3 transformation temperature 65 DEG C.
(8) cool: adopt MULPIC to cool fast at refrigerating work procedure, final cooling temperature 230 DEG C, speed of cooling 17 DEG C/s.
(9) hot straightening: adopt large straightening force at utmost to discharge stress in steel plate.
Adopt the steel plate of above explained hereafter, the mechanical property of steel plate as shown in table 6 and table 7.
Embodiment 5
The present embodiment is that the specific chemical composition of 29mmX80 is as shown in table 5.
The preparation method of a kind of low temperature large sstrain think gauge X80 Pipeline Steel Plate of the present embodiment is as follows:
(1) smelting and continuous casting: adopt Clean Steel to smelt mode, on the basis of ultralow P, S, control five large harmful element total amounts, namely these five kinds of element sums of control S, P, O, N, H are less than 130ppm, ensure purity, the homogeneity of steel.In sheet billet continuous casting process, adopt dynamic soft reduction technology, center segregation of casting blank reaches C class 1.0, and slab thickness is 300mm.
Table 529mmX80 chemical composition
(2) heating of plate blank: in the heating process of slab, slab heating temperature 1120 DEG C.
(3) thick de-scaling: the board briquette controlling thick de-scaling step is 1024 DEG C.
(4) roughing: the temperature range of recrystallization zone controlled rolling is 1005 DEG C, the lower limit 970 DEG C that last passage is meeting deformation temperature range carries out, and ensures effective combination of draft >=15% and texturing temperature.After steel plate recrystallization rolling, grain-size is grown up not too much.Workpiece thickness 130mm, accumulative draft 56.7%;
(5) intermediate blank cooling: utilize roughing mill frame high pressure descaling water to cool intermediate blank, cooling termination temperature 815 DEG C.
(6) finish rolling: the surface temperature range of Unhydrated cement controlled rolling is 730 DEG C, stops rolling temperature 690 DEG C, rolling 12-16 passage.In this stage rolling, adopt the cumulative deformation that the finish rolling stage is large, deformation induced trans-formation occurs and produces tiny proeutectoid ferrite, the grain-size of steel plate after the phase transformation of refinement simultaneously.Control 2-3 pass deformation rate is 15% simultaneously, improves distortion rate of permeation.Accumulation draft 77.7%.
(7) air cooling: after finish rolling terminates, carries out air cooling cooling to steel plate, is down to below Ar3 transformation temperature 65 DEG C.
(8) cool: adopt MULPIC to cool fast at refrigerating work procedure, final cooling temperature about 235 DEG C, speed of cooling 18 DEG C/s.
(9) hot straightening: adopt large straightening force at utmost to discharge stress in steel plate.
Adopt the steel plate of above explained hereafter, the mechanical property of steel plate as shown in table 6 and table 7.
The horizontal salient features detection statistics table of each embodiment of table 6
Longitudinal salient features detection statistics table of each embodiment of table 7
From table 6 and table 7, the performances such as the horizontal and vertical low-temperature flexibility of the pipe line steel that embodiment 1-5 obtains, uniform elongation, yield strength and tensile strength are all fine, can meet the conveying of the resource such as oil, Sweet natural gas under polar low-temperature environment.
Embodiment 6
The present embodiment is that the concrete composition of 33mmX80M is as shown in table 8.
The pipe line steel of the present embodiment is except in component, the content of zirconium is had any different, and the content of other component and preparation method, Selecting parameter are all just the same with embodiment 1
Table 833mmX80M chemical composition (%)
Adopt the mechanical property of the steel plate of above explained hereafter as shown in Table 9 and Table 10.
Embodiment 7
The present embodiment is that the concrete composition of 33mmX80M is as shown in table 9.
The pipe line steel of the present embodiment is except in component, the content of zirconium is had any different, and the content of other component and preparation method, Selecting parameter are all just the same with embodiment 1
Table 933mmX80M chemical composition (%)
Adopt the mechanical property of the steel plate of above explained hereafter as shown in Table 10 and Table 11.
The horizontal salient features detection statistics table of each embodiment of table 10
Longitudinal salient features detection statistics table of each embodiment of table 11
From table 10 and table 11, the pipe line steel that the performance such as yield strength, tensile strength of the pipe line steel that embodiment 6,7 is obtained is all obtained with embodiment 1 is similar, but the horizontal and vertical low-temperature flexibility of the pipe line steel that embodiment 1 is obtained, comparatively embodiment 6 and embodiment 7 are greatly improved uniform elongation, as can be seen here, in the present invention zirconium content range in, the low-temperature flexibility of pipe line steel is greatly increased.
By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned; but the restriction not to invention protection domain; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various amendment or distortion that creative work can make still in protection scope of the present invention.
Claims (10)
1. an X80M pipe line steel for low temperature resistant large sstrain, is characterized in that: be made up of the component of following weight part, C0.03 ~ 0.07%, Si0.15 ~ 0.35%, Mn1.50 ~ 2.00%, P≤0.009%, S≤0.002%, Nb0.06 ~ 0.09%, Ti0.015 ~ 0.020%, Zr0.015 ~ 0.025%, Mo≤0.30%, Cu≤0.35%, Ni≤0.30%, Cr≤0.30%, all the other are Fe and inevitable impurity.
2. X80M pipe line steel according to claim 1, is characterized in that: be made up of the component of following weight part, C0.05 ~ 0.06%, Si0.22 ~ 0.31%, Mn1.70 ~ 1.79%, P≤0.009%, S≤0.002%, Nb0.06 ~ 0.07%, Ti0.016 ~ 0.017%, Zr0.019 ~ 0.022%, Mo≤0.15%, Cu≤0.13%, Ni≤0.23%, Cr≤0.22%, all the other are Fe and inevitable impurity.
3. the preparation method of the X80M pipe line steel of the low temperature resistant large sstrain described in claim 1 or 2, is characterized in that: comprise the steps:
1) prepare molten iron, and molten iron is carried out desulfurization process;
2) molten iron after desulfurization is passed through smelting, refining, sheet billet continuous casting process successively, the amount of S, P, O, N, H in these three treating processess in the hierarchy of control is less than 130ppm;
3) heating of plate blank, slab heating temperature is 1050 DEG C-1150 DEG C, and soaking zone soaking time is greater than 35min, and total heat-up time is not less than 285min;
4) slab de-scaling, after de-scaling, the surface temperature of slab is 1010-1030 DEG C;
5) slab rough rolling is obtained intermediate blank, again finish rolling is carried out to intermediate blank to after intermediate blank cooling; In rough rolling process, the rolling temperature of recrystallization zone is 960-1010 DEG C, and the temperature of final pass is draft >=12% of 960-980 DEG C, final pass;
6) steel after finish rolling is cooled, before steel plate cooling, steel billet temperature is down to below transformation temperature Ar3 20-100 DEG C;
7) cooled by steel plate, final cooling temperature is 100-250 DEG C, rate of cooling 15-25 DEG C/s;
8) hot straightening is carried out to cooled steel, obtain required steel plate.
4. preparation method according to claim 3, is characterized in that: step 2) in, in described sheet billet continuous casting process, the thickness of the slab of production is 295-305mm, and after sheet billet continuous casting, by continuously cast bloom slow cooling 45-55h, center segregation of casting blank is less than C class 0.5.
5. preparation method according to claim 3, is characterized in that: step 5) in, the total deformation of rough rolling process is 50-70%, and the thickness of described intermediate blank is 100-150mm.
6. preparation method according to claim 3, is characterized in that: step 5) in, be utilize the high pressure water of 18-22MPa that the temperature of intermediate blank is down to 800-840 DEG C to the process of cooling of intermediate blank.
7. preparation method according to claim 6, is characterized in that: be utilize 18-22MPa high pressure water that the temperature of intermediate blank is down to 820 DEG C to the process of cooling of intermediate blank.
8. preparation method according to claim 3, is characterized in that: step 5) in, in finishing stands, the temperature of rolling is 680-740 DEG C, rolling 8-16 passage, and the deformation rate of front 2-3 passage is 15%, and accumulation draft is 75-80%.
9. preparation method according to claim 3, is characterized in that: step 7) in, cooling step adopts MULPIC, and final cooling temperature is 100-250 DEG C, and rate of cooling is 15-25 DEG C/s.
10. the arbitrary described application of X80M pipe line steel in severe cold areas transfer oil, Sweet natural gas of claim 1-2.
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| CN112981257A (en) * | 2021-02-09 | 2021-06-18 | 鞍钢股份有限公司 | Economical thick-wall high-strength high-toughness X70M hot-rolled steel plate and manufacturing method thereof |
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