CN101379209A - Fire-resistant high-strength rolled steel material and method for production thereof - Google Patents
Fire-resistant high-strength rolled steel material and method for production thereof Download PDFInfo
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- 239000010959 steel Substances 0.000 title claims abstract description 103
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- 239000000463 material Substances 0.000 title claims abstract description 22
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- 239000012535 impurity Substances 0.000 claims abstract description 10
- 238000000034 method Methods 0.000 claims description 45
- 238000005096 rolling process Methods 0.000 claims description 22
- 229910052719 titanium Inorganic materials 0.000 claims description 21
- 229910052796 boron Inorganic materials 0.000 claims description 18
- 229910052758 niobium Inorganic materials 0.000 claims description 17
- 238000001816 cooling Methods 0.000 claims description 15
- 238000009825 accumulation Methods 0.000 claims description 5
- 239000006104 solid solution Substances 0.000 description 49
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
- C21D8/0447—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
- C21D8/0463—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment following hot rolling
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
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- Chemical & Material Sciences (AREA)
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- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Disclosed is a fire-resistant high-strength rolled steel material which has excellent fire resistance and toughness and can be used as a structural member for a building structure. The material comprises the following components (by mass): C: not less than 0.005% and less than 0.04%; Mn: 0.8-1.7%; Si: not less than 0.05% and less than 0.4%; Nb: 0.02-1%; Ti: 0.005-0.02%; N: not less than 0.005%; B: 0.0003-0.003%; and Al: 0.005-0.03%, and has the Ti/N ratio of 2 to 8 (mass%) and the C-Nb/7.74 value of 0.02% or less, wherein the remainder is Fe and unavoidable impurities. The material has the ratio of the 0.2% proof stress at 600 DEG C to the yield strength at room temperature of 0.50 or greater.
Description
Technical field
The present invention relates to employed fire-resistant high-strength rolled steel material and manufacture method thereof such as fabric structure member.
Background technology
So-called fire-resistant steel is meant the steel for building that still have the intensity of defined under the situation that buildings is reached a high temperature by fire etc.At this, the temperature of the buildings during with presence of fire is envisioned for 600 ℃, and the fire-resistant steel of the intensity kept under this temperature is narrated.
Strengthen in the method for steel, the method for main flow has: the method and 4 of the dispersion-strengthened that the method, 3 that the sosoloid that the 1) method of ferrite crystal particle diameter miniaturization, 2) adopts alloying element to carry out is strengthened) utilizing hardens the carries out mutually) method of utilizing fine precipitate to strengthen.The distortion of steel is that arbitrary method all is the method for strengthening for the resistibility of this dislocation moving owing to moving of intragranular dislocation produces from microcosmic.
So, at first to 1) and the method for ferrite crystal particle diameter miniaturization narrates.
Dislocation in that intragranular moves stops the back earlier at crystal boundary and move to adjacent crystal grain, so crystal boundary plays the resistance (hereinafter referred to as " moving resistance ") to dislocation moving.Therefore, little if crystal grain attenuates, then dislocation of Yi Donging and the crystal boundary frequency of meeting improves, so drag increases.The method of such reinforcement moving resistance is 1) method of ferrite crystal particle diameter miniaturization.
Moreover, usually, by as Hall now the known following formula of formula come valence.
σ＝σ
0+k×d
-0.5
At this, σ is an intensity, σ
0Be base value, rate constant k is also referred to as locking parameter (LockingParameter), is the index that is illustrated in the drag at crystal boundary place, and d is a crystal particle diameter.
Then, to 2) method strengthened of the sosoloid that adopts alloying element to carry out narrates.
Under the situation of the solute atoms that has the such different size of alloying element on the all-moving surface with respect to the dislocation of mobile being called " slip plane " of dislocation, resistance (hereinafter referred to as " alloying element slip plane resistance ") plays a role.In addition, in steel, distribute, can form elastic stress field, act on as drag resistance (hereinafter referred to as " drag resistance ") for dislocation moving by making alloying element.People know, the size of this drag resistance is subjected to solute atoms concentration, results from the influence of spread coefficient of mispairing, solute atoms of solute atomic size.
By increasing the method for should " alloying element slip plane resistance " or " drag resistance " strengthening, be called 2) method strengthened of the sosoloid that adopts alloying element to carry out, and known the method that " alloying element slip plane resistance " increased.
In addition, as by increasing the solution strengthening method that " drag resistance " strengthened, the technology of the pinning effect that utilizes solid solution Nb is arranged.This utilizes the technology of the pinning effect of solid solution Nb to be applied in the manufacturing of thin fire-resistant steel, once is recorded in for example TOHKEMY 2000-054061 communique, TOHKEMY 2000-248335 communique.
The Nb that the pinning effect of so-called solid solution Nb is solid solution is in lattice imperfection enrichments such as dislocations, becomes the moving resistance of defective and dislocation and phenomenon that intensity is improved.
Present inventors have found that this pinning resistance that is produced by solid solution Nb is in the possibility that effectively plays a role up to about about 600 ℃ humidity province, thereby finished the exploitation that Nb of the present invention is fire-resistant steel, in order to give full play to the pinning effect of such solid solution Nb, finish fire-resistant steel, find to satisfy following condition with sufficient resistivity against fire.
The 1st, the amount that must make solid solution carbon is low value.If this is because solid solution carbon amount height, thereby then constitute the cause that the amount of NbC solid solution Nb reduces.
The 2nd, must add B.This is that segregation is in crystal boundary because the part of the Nb that contains can not be kept solid solution condition, and generation can not be enriched in the situation of lattice imperfection such as dislocation, but when adding B, B replaces the Nb segregation in crystal boundary, and help Nb keeps the cause of solid solution condition.
The 3rd, solid solution N amount is reduced.This is because the B and the N that add react, and generates BN, loses the cause of segregation in the ability of crystal boundary.For solid solution N amount is reduced, can use by adding Ti and generate TiN, the method that solid solution N amount is reduced.
And then, to 3) utilize the method for the dispersion-strengthened that sclerosis carries out mutually to narrate.
Hard phase and the soft macrostructure (duplex structure) that mixes existence mutually, usually intensity basis volume fraction separately changes.This results from: compare with soft, be difficult to move in the mutually intragranular dislocation of hard, it is big promptly to be out of shape pairing resistance.By making the resistance (hereinafter referred to as " hard phase resistance ") that exists mutually based on hard increase the method for strengthening, be called 3) utilize the method for the dispersion-strengthened that sclerosis carries out mutually.
For example, for the duplex structure that is made of ferrite and perlite, when increasing as the pearlitic volume fraction of hard phase, then the volume fraction as the ferritic structure of soft phase relatively reduces, thereby intensity raises.
At last, to 4) method of utilizing fine precipitate to strengthen narrates.
When intragranular dislocation moving, precipitate becomes the obstacle of dislocation under situation about being distributed on the slip plane, and the resistance of dislocation moving is played a role.With making this resistance (hereinafter referred to as " precipitate resistance ") that results from precipitate increase the method strengthen, be called 4) method of utilizing fine precipitate to strengthen.
Fire-resistant steel has in the past used: generate Mo carbide, 4 by adding Mo) method of utilizing fine precipitate to strengthen.Use Mo, by 4) utilize fire-resistant steel that the method for fine precipitate strengthens and manufacture method thereof etc. once to be recorded in TOHKEMY 2005-272854 communique, Japanese kokai publication hei 09-241789 communique.
These fire-resistant steel in the past, the C that is contained amount are about 0.1% high value, have therefore utilized not solid solution of alloying element and generate the character of precipitate.
Summary of the invention
Yet therefore, because the Mo price skyrockets, when using Mo as the leading role of alloying element solution strengthening method, begin to lose price competitiveness in recent years.
Therefore, present inventors are for use cheap Nb to replace the fire-resistant steel and the manufacture method thereof of the low price of Mo at high price to carry out investigation with great concentration as solid solution element.It found that, in order to be that the steel of solid solution element becomes the fire-resistant steel that can be used for thick steel products with Nb, has following problem.
The present invention realizes as the yield strength under the room temperature of target, hot strength, high tenacity, surface of good proterties by adjusting one-tenth balance-dividing and deoxidant element (Si, the Al) content of C, Nb, B, Ti.
The method that solves above-mentioned problem that found that present inventors concentrate on studies and develop.
At first, for problem 1, if find when making B content be 0.0003～0.003% Al content to be limited in 0.005%～0.03%, and for the content of Ti and N, making Ti/N is the amount of 2～8 scope, then can guarantee the toughness of target.
Then,,, but make it be enriched in lattice imperfections such as dislocation, found to make the value of C-Nb/7.74 to be for example necessity below 0.02% by solid solution for the Nb that makes solid solution does not become the carbide of NbC and so on and separates out for problem 2.This is equivalent to solid solution C is below 0.02%.
At last, for problem 3, find that making Ti/N be under the situation of amount of 2～8 scope, in order to ensure the generation of strength of parent and inhibited oxidation skin defective, as long as the content of Si is suppressed to less than 0.4%.
And find that under solid solution C was situation 0.02% below, because the solid solution of Nb, " drag resistance " increase can be expected significantly solution strengthening.Find should " drag resistance " to be subjected to solute atoms concentration, result from the influence of spread coefficient of mispairing, solute atoms of solute atomic size, under this condition, this effect of Nb is bigger.Finding in addition, by the strengthening effect that the pinning effect of solid solution Nb brings, is about 5～8 times of the strengthening effect that brings of the interpolation by Mo of fire-resistant steel in the past, and the interpolation of the alloy by less amount can be guaranteed equal hot strength.
As previously discussed, according to the present invention,, can realize yield strength, hot strength, high tenacity, surface of good proterties under the room temperature of target by adjusting the one-tenth balance-dividing of C, Nb, B, Ti, Al, Si.
Under described opinion, according to the present invention, a kind of fire-resistant high-strength rolled steel material can be provided, it contains more than the C:0.005% in quality % and less than 0.04%, Mn:0.8～1.7%, more than the Si:0.05% and less than 0.4%, Nb:0.02～1%, Ti:0.005～0.02%, below the N:0.005%, B:0.0003～0.003%, Al:0.005%～0.03%, and in quality %, Ti/N is in 2～8 scope, C-Nb/7.74 is below 0.02%, its surplus is made up of Fe and unavoidable impurities, and 0.2% proof strength under 600 ℃ is more than 0.50 with the ratio of yield strength at room temperature.
In addition, under the inexplicit situation of yield strength at room temperature, adopt 0.2% proof strength, but when calculating 0.2% proof strength, adopt the offset distance method of JIS Z 2241.
This fire-resistant high-strength rolled steel material in quality %, can further contain more than any one or two kinds of that Cr:0.4% is following, Cu:1% is following, Ni:1.0% is following.
In addition, according to the present invention, a kind of manufacture method of fire-resistant high-strength rolled steel material can be provided, to contain more than the C:0.005% and less than 0.04% in quality %, Mn:0.8～1.7%, more than the Si:0.05% and less than 0.4%, Nb:0.02～1%, Ti:0.005～0.02%, below the N:0.005%, B:0.0003～0.003%, Al:0.005%～0.03%, and in quality %, Ti/N is in 2～8 scope, C-Nb/7.74 is below 0.02%, beginning was rolling after the strand that its surplus is made up of Fe and unavoidable impurities was heated to 1250～1350 ℃ humidity province, carrying out at the accumulation draft below 1000 ℃ is rolling more than 30%, described fire-resistant high-strength rolled steel material, 0.2% proof strength under 600 ℃ is more than 0.50 with the ratio of yield strength at room temperature.
In addition, according to the present invention, a kind of manufacture method of fire-resistant high-strength rolled steel material can be provided, to contain more than the C:0.005% and less than 0.04% in quality %, Mn:0.8～1.7%, more than the Si:0.05% and less than 0.4%, Nb:0.02～1%, Ti:0.005～0.02%, below the N:0.005%, B:0.0003～0.003%, Al:0.005%～0.03%, and in quality %, Ti/N is in 2～8 scope, C-Nb/7.74 is below 0.02%, beginning was rolling after the strand that its surplus is made up of Fe and unavoidable impurities was heated to 1250～1350 ℃ humidity province, finishing back average cooling rate with 0.1～10 ℃/second in 800～500 ℃ temperature range at the rolling cools off, described fire-resistant high-strength rolled steel material, 0.2% proof strength under 600 ℃ is more than 0.50 with the ratio of yield strength at room temperature.
Moreover for these manufacture method, the inexplicit occasion of yield strength at room temperature adopts 0.2% proof strength.
In these manufacture method, above-mentioned strand can further contain more than any one or two kinds of below the Cr:0.4%, below the Cu:1%, below the Ni:1.0% in quality %.
According to the present invention, can provide and have high strength and high tenacity, by bringing into play the pinning effect of solid solution Nb to greatest extent, do not add the Mo that generally in fire-resistant steel, adds fully, only by solid solution Nb, even under 600 ℃, also have the steel of fire performance excellence of the proof strength more than 1/2 of room temperature.
Description of drawings
Fig. 1 is the figure that fastens the expression proper range in the pass of Nb and C.
Fig. 2 is the figure that fastens the expression proper range in the pass of Ti and N.
Fig. 3 is the figure that is used to illustrate the pinning effect of Nb, (a) is the figure that adds under the situation of Nb and B, (b) is the figure that only adds separately under the situation of Nb.
Fig. 4 is the sketch of the routine example of the device configuration of expression enforcement the inventive method.
Fig. 5 is the figure of the sample preparation position of the section form of expression H shaped steel and mechanical test piece.
Embodiment
Below the composition range of fire-resistant steel of the present invention and the control condition of composition range are narrated.Moreover each composition range is represented with quality %.
C: in order to improve hardening capacity, obtain as the essential intensity of structural steel, need be for more than 0.005%.Preferred C content is more than 0.01%.
Yet, for the strengthening effect that the pinning effect that obtains by solid solution Nb brings, need be less than 0.04%.This is that a large amount of Nb separates out with the NbC form owing to be 0.04% when above, helps the high cause of possibility of amount minimizing of the solid solution Nb of solution strengthening.For the strengthening effect that the pinning effect that obtains by solid solution Nb brings, C is preferably below 0.02%.
Moreover, as described later, if C-Nb/7.74 in the scope below 0.02%, then can guarantee the amount of solid solution Nb.In addition, by reducing C content, the B by adding also has the Fe of preventing then
23(CB)
6The effect of separating out.
Mn: improve, guarantee the intensity and the toughness of mother metal in order to make hardening capacity, must add more than 0.8% that Mn is the element that causes center segregation when making steel billet in continuous casting, when addition surpassed 1.7%, hardening capacity excessively rose in segregation portion, and toughness worsens.In view of the above, the scope of Mn content is defined as 0.8～1.7%.
Si: be 0.4% when above, in the reheat of strand, generate low-melting Fe
2SiO
4Compound worsens the oxide skin separability, and surface imperfection takes place, but in order to ensure the intensity of mother metal, and for the pre-deoxidation of the molten steel under the situation of the addition of restriction Al as described later, must add more than 0.05%.Be the occasion of 2～8 scope at Ti/N described later, in order to ensure the generation of the intensity and the inhibited oxidation skin defective of mother metal, as long as the content that makes Si less than 0.4%, so Si content is defined as more than 0.05% and less than 0.4%.For by preventing that scale defects from further improving surface texture, Si content is preferably below 0.2%.
Nb: be important element in the present invention, hardening capacity significantly raise, improve yield strength at room temperature thus,, add more than 0.02% in addition for the purpose that hot strength is increased by solid solution Nb and B coexistence.But when surpassing 1%, the effect that Nb adds is saturated, so the upper limit is defined as 1%.In the present invention, can produce effect to greatest extent, therefore be typically below 0.1%, can obtain effect of sufficient when being the Nb addition below 0.05% under the good situation of the balance of other composition as the necessary solid solution Nb of fire-resistant steel.The addition of regulation Nb not only for the pinning effect that utilizes Nb guarantees sufficient resistivity against fire, and in order fully to obtain the amount as solid solution Nb, following condition is necessary.
Under the situation of Nb solid solution, " drag resistance " that caused by the pinning effect of solid solution Nb improves, and helps to strengthen.Therefore but Nb is the strong carbide forming element, if having C then form NbC, and solid solution Nb is reduced, and the strengthening mechanism that is produced by pinning effect dies down.
In the present invention, in order to obtain for strengthening sufficient solid solution Nb,, found out that must make C-Nb/7.74 is below the 0.02% quality % as the addition of Nb relation with respect to the addition of C.At this, during scope below C-Nb/7.74 is 0.02% quality %, Nb and C disassemble, and can guarantee necessary Nb solid solution capacity, fully help the necessary solution strengthening of resistivity against fire.
Above content is put in order, and the addition of Nb and C and interpolation equilibrated proper range are as shown in Figure 1.Promptly, be required to be (b) more than 0.005% in order to ensure intensity C addition, and, need less than 0.04% (c) in order to ensure toughness, in order to ensure hot strength, the addition that the addition of Nb is required to be (a) more than 0.02% and Nb needs Nb is restricted to (C-0.02) * 7.74 above (d) for the addition of C.
N: generate these nitride of NbN, BN, reduce the hardening capacity of Nb, B, make the lath border of bainite form high-carbon island martensite body in addition, make the toughness deterioration, therefore N content is limited in below 0.005%.Moreover, usually in unavoidable impurities, contain the N about 20～30ppm, therefore preferably be suppressed at below 0.003%.
Al: be for steel liquid deoxidation, fully obtain room temperature and pyritous intensity is added, need to add more than 0.005%.But especially the occasion of shaped steel and Plate Steel surpasses under 0.03% the situation at addition, can form the island martensite body, and toughness is worsened, and the hot strength in butt welded seam district also causes detrimentally affect in addition, therefore must be defined as below 0.03%.Further require the occasion of the thermal embrittlement characteristic again of base metal tenacity and weld metal zone as thick steel products, be limited in below 0.015% and get final product, further be constrained to,, can obtain effect to greatest extent from the viewpoint of Al addition less than 0.01% o'clock.
The effect of adding Ti roughly has 2 points.
The 1st point, for by TiN separate out refinement γ (austenite) crystal grain, and, solid solution B amount is increased in order to suppress separating out of BN, NbN by reducing solid solution N, improve the hardening capacity rising effect of B and add Ti.Thus, at room temperature yield strength and hot strength are raise.Less than 0.005% o'clock, TiN separated out quantity not sufficient, can not bring into play these effects at addition, and therefore the lower value with the Ti amount is defined as 0.005%.The Ti of the surplus above 0.02% can separate out thick Ti (CN), makes the toughness deterioration of mother metal and welded heat affecting zone, therefore is limited to below 0.02%.
The solid solution N amount of the 2nd pinning effect decay that is to reduce to make Nb.
Result through investigation with great concentration knows that in quality %, Ti/N suits in 2～8 scope.This be because at Ti/N less than 2 o'clock, be not enough to solid solution N is fixed with the TiN form; Surpass at 8 o'clock at Ti/N, superfluous Ti forms thick Ti (CN) makes the toughness deterioration.By limiting this Ti/N, can fully guarantee toughness as thick steel products, make full use of the hardening capacity of bringing by B to greatest extent, obtain hot strength as fire-resistant steel, if the Ti/N value is controlled at more than 2.5, below 6, then can access better characteristic.
Put the above in order, the scope of the suitable addition of Ti, Nb as shown in Figure 2.That is, about the Ti addition, in order to ensure the amount of separating out of TiN, be required to be (a) more than 0.005%, and, be required to be (b) below 0.02% in order to suppress separating out of thick Ti (CN), N content is required to be (c) below 0.005%, and Ti/N is required to be (e) more than 2, (d) below 8.
The purpose of adding B has two.
On the meaning that purpose 1 and purpose 2 are set up to greatest extent simultaneously, preferably add 0.001～0.002% B.
Cr: effective to the reinforcement of mother metal by improving hardening capacity.But the interpolation of the surplus above 0.4% becomes harmful from toughness and indurative viewpoint, therefore the upper limit is defined as 0.4%.
Cu: effective to the reinforcement of mother metal by improving hardening capacity.But the interpolation of the surplus above 1% becomes harmful from toughness and indurative viewpoint, therefore the upper limit is defined as 1%.
Ni: effective to the reinforcement of mother metal by improving hardening capacity.But, the upper limit is defined as 1.0% from the viewpoint of economy.
The P and the S that contain as unavoidable impurities are not particularly limited its content, but owing to solidifying segregation produces welding crack and flexible reduction, therefore must do one's utmost to reduce.P content is preferably below 0.03%, and S content is preferably below 0.02%.
To have strand that above-mentioned composition, its surplus be made of Fe and unavoidable impurities, to be heated to surface temperature be behind 1250～1350 ℃ the humidity province, to begin rolling.The reason that reheat to the surface temperature of strand becomes 1250～1350 ℃ humidity province be because, for with chien shih Nb solutionizing in short-term, obtain mother metal and strengthen necessary solid solution Nb, preferred heating more than 1250 ℃, in order when making shaped steel, to make viscous deformation easy, need carry out the heating more than 1250 ℃ in addition by hot-work.Moreover performance and economy from process furnace are defined as 1350 ℃ with the Heating temperature upper limit.
The strand that surface temperature is heated to 1250～1350 ℃ humidity province carries out hot rolling like this.In its hot rolling, be rolling more than 30% by carrying out at the accumulation draft below 1000 ℃, based on the processing recrystallize, γ crystal grain obtains refinement, can seek the high tenacityization and the high strength of steel thus.
This hot rolling is cooled off at the average cooling rate of 800～500 ℃ temperature ranges with 0.1～10 ℃/second after finishing.The reason that the refrigerative temperature range is defined as 800～500 ℃ is in order to ensure solid solution Nb.In addition, with average cooling rate be defined as 0.1～10 ℃/second reason be because, when average cooling rate during less than 0.1/ second, the hardening capacity deficiency; When average cooling rate surpasses 10 ℃/second, generate martensite, make the significantly reduced cause of base metal tenacity.
Even the feature of composition of steel of the present invention is that also average cooling rate is 0.1 ℃/second and also can guarantees sufficient hardening capacity, applicable to thick steel, for example edge of a wing thickness is the suitable utmost point thick h shape steel of 125mm.In addition, in the present invention, by adding B and Nb, the beginning of phase transformation is postponed in continuous cooling process, and by being made as above-mentioned speed of cooling, the γ of phase transformation does not remain to lower temperature with supercooled state, because the velocity of diffusion of Nb reduces, and NbC can not be separated out, Nb supersaturation and solid solution.
Fire-resistant high-strength rolled steel material of the present invention, can perform well in the structural member of buildings etc., specifically, shaped steel such as uniform thickness angle-steel and for example thickness of slab are not that Plate Steel more than the 7mm is specialized as H shaped steel, I shaped steel, angle-steel, U-steel, scalene.
In addition, for example under above-mentioned condition, as an example of fire-resistant high-strength steel of the present invention, make the occasion of H shaped steel, still have sufficient toughness for edge of a wing thickness of slab 1/2 part that is difficult to guarantee most for mechanical testing characteristic in the H shaped steel, wide 1/2 part.
In addition, by strengthening effect, can obtain to have excellent fire performance and flexible high-strength fireproof rolling H shaped steel based on the anchoring effect of solid solution Nb.In addition, the hot properties excellence of this H shaped steel, therefore in the occasion that is used for refractory materials for building, lining thickness in the past 50% can reach sufficient fire-resistant purpose when following.
Embodiment
Further show effect of the present invention by the following examples.
With the strand heating of each steel grade shown in the table 1, carried out rolling.Specifically, converter refining trial-production steel adds Ti, B after the interpolation alloying constituent, by continuous casting, is cast as the strand that thickness is 240～300mm.After the strand heating, form H shaped steel (the thick 28mm in the thick 18mm * edge of a wing of wide 405mm * web, the high 414mm * edge of a wing of web) by hot rolling.
When rolling, in universal rolling unit shown in Figure 4, make from what process furnace 1 came out and be rolled material (strand) 5 successively by roughing mill 2, intermediate mill 3, finishing mill 4.
In milling train, as shown in Figure 5, be rolled into H shaped steel with the H shape section form that constitutes by the web 6 and a pair of edge of a wing 7.
In addition, during water-cooled between rolling pass, front and back at intermediate mill 3 are provided with water cooling plant, spray cooling and rolling the carrying out repeatedly of reversible (reverse) by edge of a wing outer side, acceleration cooling after rolling, be in finishing mill 4, after the rolling end, to adopt and edge of a wing outer side is sprayed cooling at its refrigerating unit that is provided with later.
In each steel (H shaped steel), at the thickness of slab t that is the edge of a wing 7
2Central part (1/2t
2) and be the position of flange width total length B half (1/2B), prepare test piece respectively, investigated mechanical characteristics.
It is optimum to judge on the mechanical testing characteristic of estimating H shaped steel this position, and its reason is that the mechanical characteristics of H shaped steel of edge of a wing 1/2B part is minimum.
Mechanical testing characteristic as each steel (H shaped steel), be illustrated in yield strength (the yield point stress YP (MPa) under the room temperature (21 ℃) respectively, under its inexplicit situation, adopt 0.2% proof strength) and tensile strength (TS (MPa)), in 0.2% proof strength under 600 ℃ (600YS (MPa)), in ratio (600YS/YP than (%)), impact value (vE0 ℃ (J)), the yield ratio (YR) of the proof strength under 600 ℃ (600YS) with yield strength (yield point stress YP) under room temperature (21 ℃).
Qualified benchmark as each mechanical testing characteristic, be that tensile strength TS under room temperature (21 ℃) is, yield strength (YP) is the high strength 235MPa more than more than the 400MPa, and to require in 0.2% proof strength (600YS) under 600 ℃ be that summer more than 50%, under 0 ℃ of the yield strength (yield point stress YP) under room temperature (21 ℃) is more than the 47J than impact absorbing energy value (vE0).This is because if meet this qualified benchmark, just can judge that as the resistivity against fire steel be suitable.
Table 1 illustrates the chemical ingredients value of employed each steel grade of embodiment and the mechanical characteristics of H shaped steel.
Each H shaped steel of No.1 within the scope of the invention～14 all satisfies above-mentioned qualified benchmark.Even each H shaped steel in the scope of the invention is the edge of a wing thickness of slab 1/2t that the mechanical testing characteristic of rolled section steel is difficult to guarantee most
2, width 1/2B part also has full intensity and toughness, is the shaped steel of resistivity against fire and tenacity excellent.
For comparative example No.17, though the mechanical testing characteristic can satisfy, add the once oxidation skin adherence of pining for generating and remain in and become scale defects on the end article, be to be not suitable for the grade used as steel for building.
Then, the embodiment shown in the his-and-hers watches 2 describes.
For the steel of the No.1 in the table 1, No.13, the change Heating temperature, at the accumulation draft below 1000 ℃, make H shaped steel (the high 414mm of web * flange width 405mm * web thickness 18mm * edge of a wing thickness 28mm), investigated the mechanical testing characteristic.The No.1 of table 2, No.13 are Production Examples of the present invention, satisfy characteristic benchmark of the present invention.
Shown in the No.30,31,32,33 of table 2, for Heating temperature less than 1250 ℃ situation and at the accumulation draft below 1000 ℃ less than for 30% the situation, can not satisfy characteristic benchmark of the present invention.
For the No.9 of table 1, the steel of No.14, Heating temperature is made as 1300 ℃, the average cooling rate of the temperature range that the change of rolling back is 800～500 ℃, make H shaped steel (the high 414mm of web * flange width 405mm * web thickness 18mm * edge of a wing thickness 28mm and the high 608mm of web * flange width 477mm * web thickness 90mm * edge of a wing thickness 125mm), investigated the mechanical testing characteristic.The No.9 of table 2,14,34, the 35th, Production Example of the present invention satisfies characteristic benchmark of the present invention.
Shown in the No.36,37,38,39 of table 2, average cooling rate for example is under the situation of 0.05 ℃/second or 15.00 ℃/second beyond 0.1～10 ℃/second scope, can not satisfy characteristic benchmark of the present invention.
In addition, among the embodiment typical rolling stock H shaped steel is verified, but the present invention is not limited to the H shaped steel of the foregoing description as the rolling stock of object, also go for not steel such as various shaped steel, slab such as uniform thickness angle-steel of I shaped steel, angle-steel, U-steel, scalene, in addition, under the thicker situation of thickness of slab, also can make.
Utilize possibility on the industry
According to the present invention, have resistivity against fire and flexible shaped steel etc. by rolling the manufacturing, structural member by fire-resistant steel of the present invention being used for buildings etc., can realize shortening the significantly cost cutting that brings by construction cost, duration, can improve building reliability, guarantee security, improve economy etc.
In the present invention, the expression numerical range " more than " and " following " include given figure.
Claims (6)
1. fire-resistant high-strength rolled steel material, it is characterized in that, in quality %, contain more than the C:0.005% and less than 0.04%, Mn:0.8～1.7%, more than the Si:0.05% and less than 0.4%, Nb:0.02～1%, Ti:0.005～0.02%, below the N:0.005%, B:0.0003～0.003%, Al:0.005%～0.03%, and in quality %, Ti/N is in 2～8 scope, C-Nb/7.74 is below 0.02%, its surplus is made up of Fe and unavoidable impurities, 0.2% proof strength under 600 ℃ is more than 0.50 with the ratio of yield strength at room temperature, wherein said yield strength at room temperature is 0.2% proof strength under the inexplicit situation of yield-point.
2. fire-resistant high-strength rolled steel material according to claim 1 in quality %, also contains more than any one or two kinds of that Cr:0.4% is following, Cu:1% is following, Ni:0.7% is following.
3. the manufacture method of a fire-resistant high-strength rolled steel material, it is characterized in that, to contain more than the C:0.005% and less than 0.04% in quality %, Mn:0.8～1.7%, more than the Si:0.05% and less than 0.4%, Nb:0.02～1%, Ti:0.005～0.02%, below the N:0.005%, B:0.0003～0.003%, Al:0.005%～0.03%, and in quality %, Ti/N is in 2～8 scope, C-Nb/7.74 is below 0.02%, beginning was rolling after the strand that its surplus is made up of Fe and unavoidable impurities was heated to 1250～1350 ℃ humidity province, carrying out at the accumulation draft below 1000 ℃ is rolling more than 30%, 0.2% proof strength of described fire-resistant high-strength rolled steel material under 600 ℃ is more than 0.50 with the ratio of at room temperature yield strength, wherein said yield strength at room temperature is 0.2% proof strength under the inexplicit situation of yield-point.
4. the manufacture method of fire-resistant high-strength rolled steel material according to claim 3, above-mentioned steel billet also contains more than any one or two kinds of below the Cr:0.4%, below the Cu:1%, below the Ni:0.7% in quality %.
5. the manufacture method of a fire-resistant high-strength rolled steel material, it is characterized in that, to contain more than the C:0.005% and less than 0.04% in quality %, Mn:0.8～1.7%, more than the Si:0.05% and less than 0.4%, Nb:0.02～1%, Ti:0.005～0.02%, below the N:0.005%, B:0.0003～0.003%, Al:0.005%～0.03%, and in quality %, Ti/N is in 2～8 scope, C-Nb/7.74 is below 0.02%, beginning was rolling after the strand that its surplus is made up of Fe and unavoidable impurities was heated to 1250～1350 ℃ humidity province, finishing the back at the rolling cools off at 800～500 ℃ the temperature range average cooling rate with 0.1～10 ℃/second, 0.2% proof strength of described fire-resistant high-strength rolled steel material under 600 ℃ is more than 0.50 with the ratio of at room temperature yield strength, wherein said yield strength at room temperature is 0.2% proof strength under the inexplicit situation of yield-point.
6. the manufacture method of fire-resistant high-strength rolled steel material according to claim 5, above-mentioned steel billet also contains more than any one or two kinds of below the Cr:0.4%, below the Cu:1%, below the Ni:0.7% in quality %.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006030962 | 2006-02-08 | ||
| JP030962/2006 | 2006-02-08 |
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| Country | Link |
|---|---|
| US (1) | US20090020190A1 (en) |
| EP (1) | EP1983069A4 (en) |
| JP (1) | JP5114743B2 (en) |
| KR (1) | KR101018055B1 (en) |
| CN (1) | CN101379209A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104561819A (en) * | 2014-11-26 | 2015-04-29 | 南京钢铁股份有限公司 | Q460-grade fire-resistant weathering steel and preparation method thereof |
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| DE102004062739A1 (en) * | 2004-12-27 | 2006-07-06 | Degussa Ag | Self-cleaning surfaces with protrusions formed by hydrophobic particles, with improved mechanical strength |
| JP4741528B2 (en) * | 2007-02-09 | 2011-08-03 | 新日本製鐵株式会社 | Steel plates and steel pipes for steam transport piping having excellent high temperature characteristics and methods for producing them |
| CN102400049B (en) * | 2010-09-07 | 2014-03-12 | 鞍钢股份有限公司 | 490-grade fireproof steel plate for building structure and manufacturing method thereof |
| CN102851596B (en) * | 2011-06-28 | 2015-10-07 | 鞍钢股份有限公司 | A kind of low cost 490MPa level building structure refractory steel plates and manufacture method thereof |
| WO2013089156A1 (en) | 2011-12-15 | 2013-06-20 | 新日鐵住金株式会社 | High-strength h-section steel with excellent low temperature toughness, and manufacturing method thereof |
| JPWO2014175122A1 (en) | 2013-04-26 | 2017-02-23 | 新日鐵住金株式会社 | H-section steel and its manufacturing method |
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| JPS5877528A (en) * | 1981-10-31 | 1983-05-10 | Nippon Steel Corp | Manufacture of high tensile steel with superior toughness at low temperature |
| JPH07286233A (en) * | 1994-04-19 | 1995-10-31 | Nippon Steel Corp | Low yield ratio steel for building excellent in fire resistance and its production |
| JPH08333651A (en) * | 1995-06-06 | 1996-12-17 | Nippon Steel Corp | Steel material excellent in heat-affected zone hardening resistance |
| JP3817064B2 (en) * | 1998-04-22 | 2006-08-30 | 新日本製鐵株式会社 | Low yield ratio type fire-resistant hot-rolled steel sheet and steel pipe and method for producing them |
| JP3559455B2 (en) * | 1998-08-10 | 2004-09-02 | 新日本製鐵株式会社 | Low-yield-ratio type refractory steel, steel pipe, and method for producing the same |
| JP4276324B2 (en) | 1999-02-26 | 2009-06-10 | 新日本製鐵株式会社 | Low yield ratio fire-resistant hot-rolled steel sheet and steel pipe excellent in toughness, and methods for producing them |
| JP3635208B2 (en) | 1999-03-29 | 2005-04-06 | 新日本製鐵株式会社 | Low yield ratio fireproof steel plate and steel pipe excellent in toughness and method for producing the same |
| JP2001262225A (en) * | 2000-03-14 | 2001-09-26 | Nkk Corp | Method for producing exra-thick wide flange shape |
| JP4362219B2 (en) * | 2000-10-11 | 2009-11-11 | 新日本製鐵株式会社 | Steel excellent in high temperature strength and method for producing the same |
| JP2002146484A (en) | 2000-11-10 | 2002-05-22 | Sanyo Special Steel Co Ltd | High strength ferritic heat resistant steel |
| JP2002294391A (en) * | 2001-03-29 | 2002-10-09 | Kawasaki Steel Corp | Steel for building structure and production method therefor |
| JP2004360361A (en) * | 2003-06-06 | 2004-12-24 | Nippon Steel Corp | Steel structure without fireproofing coating |
| JP2005194869A (en) * | 2003-12-10 | 2005-07-21 | Nippon Steel Corp | Steel structure capable of omitting or reducing fireproof coating |
| JP4631299B2 (en) * | 2004-03-25 | 2011-02-16 | Ｊｆｅスチール株式会社 | Low yield ratio rolled H-section steel excellent in fire resistance and manufacturing method thereof |
-
2007
- 2007-02-08 EP EP07708393A patent/EP1983069A4/en not_active Withdrawn
- 2007-02-08 JP JP2007557917A patent/JP5114743B2/en not_active Expired - Fee Related
- 2007-02-08 KR KR1020087016006A patent/KR101018055B1/en active IP Right Grant
- 2007-02-08 CN CNA2007800048687A patent/CN101379209A/en active Pending
- 2007-02-08 US US12/223,690 patent/US20090020190A1/en not_active Abandoned
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| CN104561819A (en) * | 2014-11-26 | 2015-04-29 | 南京钢铁股份有限公司 | Q460-grade fire-resistant weathering steel and preparation method thereof |
| CN104561819B (en) * | 2014-11-26 | 2017-05-24 | 南京钢铁股份有限公司 | Q460-grade fire-resistant weathering steel and preparation method thereof |
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| US20090020190A1 (en) | 2009-01-22 |
| EP1983069A4 (en) | 2011-03-02 |
| WO2007091725A1 (en) | 2007-08-16 |
| EP1983069A1 (en) | 2008-10-22 |
| JPWO2007091725A1 (en) | 2009-07-02 |
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| JP5114743B2 (en) | 2013-01-09 |
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