CN102337482B - Bainite high strength and toughness steel plate with yield strength of 900 MPa and manufacture method thereof - Google Patents
Bainite high strength and toughness steel plate with yield strength of 900 MPa and manufacture method thereof Download PDFInfo
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Abstract
The invention relates to a bainite high strength and toughness steel plate with the yield strength of 900 MPa and its manufacture method. The chemical composition of the steel plate (weight percent wt.%) comprises: 0.07-0.14% of C, 0.25-0.50% of Si, 1.70-2.20% of Mn, 0.05-0.50% of Cr, 0.20-0.50% of Ni, 0.03-0.10% of Nb, 0.03-0.10% of V, 0.01-0.04% of Ti, 0.02-0.04% of Al, 0.0006-0.0025% of B, the balance of Fe and inevitable impurity. The method adopts a thermo-mechanical controlled rolling technology and a cooling technology to obtain an organization with an ultra-fine bainite lath as a matrix, the yield strength of the steel plate is greater than or equal to 900 MPa, the tensile strength is greater than or equal to 980 MPa, the Charpy impact energy Akv (20 DEG C below zero) is more than 150 J, the weld crack sensitivity index Pcm is less than or equal to 0.25%, the steel plate has good welding performance.
Description
Technical field
The present invention relates to high strength low-temperature high-toughness steel plate, specifically, the present invention relates to yield strength 900MPa level bainite type high strength steel plate and manufacture method thereof.
Background technology
The heat engine tool of steel plate is processed the controlled rolling and controlled cooling mode (TMCP) that usually adopts.Realize the refinement of microtexture or form the contour intensity tissue of ultra-fine bainite by controlling deformation rate and speed of cooling, improve the yield strength of steel.
Prior art has the document of introducing bainite high-strength steel, easy welding high-strength steel and high strength steel plate.Publication number is that the Chinese patent application of CN1786246 discloses " high tensile strength high toughness low yield ratio bainite steel and production method thereof ", this steel plate has 800MPa tensile strength, ductile-brittle transition temperature is below-60 ℃, and its chemical composition (wt.%) is C:0.08～0.15%, Si:0.26～0.46%, Mn:1.5～1.7%, Nb:0.015～0.060%, Ti:0.005～0.03%, B:0.0005～0.003%, Mo:0.2～0.5%, Cu:0.4～0.6%, Ni:0.26～0.40%, Al:0.015～0.05%.It is a kind of with the low-alloy high-strength steel of two temperature stages with the TMCP explained hereafter that publication number is that the international application of WO99/05335 discloses, tensile strength with 930MPa,-20 ℃ of ballistic works are 120J, and its chemical composition (wt.%) is: C:0.05～0.10%, Mn:1.7～2.1%, Ni:0.2～1.0%, Mo:0.25～0.6%, Nb:0.01～0.10%, Ti:0.005～0.03%, P≤0.015%, S≤0.003%.
The alloying element design of above-mentioned disclosed two kinds of steel grades is respectively Mn-Ni-Nb-Mo-Ti and Mn-Mo-Ni-Cu-Nb-Ti system, because Mo is precious alloy, therefore analyze from the kind of the alloying element that adds and the total amount that adds, prepare this type of steel grade cost higher.
Summary of the invention
In order to overcome the above problems, it is steel grade that the present inventor adopts Si-Mn-Cr-Ni-Nb-V-Ti-Al-B, by controlling thermo-mechanical rolling and cooling technology, and without modifier treatment, prepared the low-carbon (LC) that a kind of yield strength reaches the 900MPa level and had low temperature superhigh tenacity and the low steel plate of welding crack sensibility index, this steel plate has good low-temperature flexibility and weldability.
One object of the present invention is to provide a kind of yield strength 900MPa level bainite type high strength steel plate.
Another object of the present invention is to provide the manufacture method of described superstrength, high tenacity, the low steel plate of welding crack sensibility index.
To achieve these goals, the chemical composition (weight percentage wt.%) of yield strength 900MPa level bainite type high strength steel plate of the present invention comprises: C:0.07～0.14%, Si:0.25～0.50%, Mn:1.70～2.20%, Cr:0.05～0.50%, Ni:0.20～0.50%, Nb:0.03～0.10%, V:0.03～0.10%, Ti:0.01～0.04%, Al:0.02～0.04%, B:0.0006～0.0025%, surplus are Fe and inevitable impurity.
Yield strength 〉=the 900MPa of steel plate, tensile strength 〉=980MPa, Xia Shi Impact energy Ak v (20 ℃) be greater than 150J, welding crack sensibility indices P cm≤0.25%.
The manufacture method of above-mentioned yield strength 900MPa level bainite type high strength steel plate comprises:
Smelting, casting, heating, rolling, cooling and tempering process;
In heat-processed, heating and temperature control is at 1080～1280 ℃;
Rolling is divided into first stage and subordinate phase rolling; The first stage rolling is carried out more than recrystallization temperature, treat on roller-way after the first stage rolling that temperature carries out the subordinate phase rolling to 770～860 ℃, and finishing temperature is 760～840 ℃;
Carry out after rolling cooling, preferably, steel plate with the speed of 12～45 ℃/s be cooled to≤400 ℃, air cooling after water outlet;
Carry out tempering heat treatment after cool to room temperature, tempering temperature is 350～500 ℃, air cooling after tempering.Preferably, air cooling employing stacking or cold bed are cooling.
Adopted improved TMCP and relaxation to control during thermal treatment of the present invention and separated out (RPC) technology, air cooling relaxation for some time after rolling, made carbonitride form disperse and tiny separating out in dislocation and subgrain boundary place.Carry out the subordinate phase rolling after relaxation, accelerate cooling after the subordinate phase rolling.The ultimate principle of technological process is:
Steel plate fully is out of shape in recrystallization zone, and the dislocation desity in austenite increases.The dynamic recovery that occurs in the operation of rolling and recrystallization softening original austenite grain.There is the hydrostaticpressure field of force in edge dislocation, and interstitial atom such as B etc. can the enrichments of dispiration place.Subgrain boundary can be described with dislocation model, and interstitial atom can be to the enrichment of subgrain boundary place.The enrichment of interstitial atom makes the dislocation place form the Cottrell air mass, has hindered high density dislocation process evolution in Recovery Process that distortion causes, and has formed the stable network of dislocation.In relaxation process, the microalloy elements such as Nb, V, Ti are separated out at crystal boundary, subgrain boundary and dislocation place with the carbonitride of the different chemicals such as (Nb, V, Ti) x (C, N) y metering ratio.The two-phase particles such as the carbonitride of separating out, pinning dislocation and the subgrain boundary in crystal grain, stablized as substructures such as dislocation walls.
Carry out the subordinate phase rolling after relaxation, the dislocation desity in steel is further increased.Relaxation after strain steel plate enters accelerated cooling device, and cooling rate has been avoided the C curve of ferrite and pearlite in CCT figure faster, directly enters the bainite transformation district.The nucleation rate process of bainite has been subject to the impact of following factor:
(1) learn angle analysis from thermodynamics, austenite has larger condensate depression, and a large amount of defects is arranged in austenite, and defect can provide the defect energy, and the two all can increase phase driving force, and the bainite nucleation rate is increased;
(2) from the crystallography angle analysis, a large amount of defects in austenite cause in lattice the zone that exists a lot of mismatch higher, and bainite is easier of the sub-region forming core;
(3) from the crystalline structure angle analysis, separate out in relaxation process a large amount of tiny and carbonitride of disperse provides a large amount of potential nucleation sites.
Due to the impact of above-mentioned three reasons, bainite has very high nucleation rate.Growing up of bainite lamella is subjected to the impact of following reason:
(1) from the thermodynamics analysis, the Interface Motion of alloying element atom pairs scattering nature, by solute effect of dragging dissipation free energy, has reduced Growth of Bainite speed;
(2) driven mechanics angle analysis, lower transition temperature, reduced the velocity of diffusion of carbon atom and iron atom, the coarsening rate of having slowed down bainite ferrite;
(3) from the crystalline structure angle analysis, bainite after the subgrain boundary forming core, is subject to the obstruction of the place ahead subgrain boundary in growth process.In the austenite Recovery Process, the motion of dislocation is subject to the pinning of second phase particles, has therefore formed a large amount of subgrain boundaries.Through the subgrain boundary that develops, growing up of bainite there is restraining effect.
Above three reasons cause the coarsening rate of bainite ferrite and the final lengths of bainite ferrite to be suppressed.This technique is to promoting forming core and suppressed the combined action refinement of growing up the bainite ferrite lath of final tissue.
For the high-strength steel that physical construction and engineering construction are used, need before weldering not preheating or preheating and not cracking a little, be mainly the welding procedure problem that has solved large-scale steel structure members.The only resource that reduces Pcm is exactly the add-on that reduces carbon and alloying element, and for the high-strength steel that adopts the quenching+tempering explained hereafter, reduce the add-on of carbon and alloying element and will inevitably bring the reduction of hardness of steel, adopt improved TMCP+RPC technique in the present invention, can make up this defect.The welding crack sensibility indices P cm of steel plate can determine by following formula
Pcm＝C+Si/30+Ni/60+(Mn+Cr+Cu)/20+Mo/15+V/10+5B
Welding crack sensibility indices P cm is the judgement index of the welding cold cracking tendency of reflection steel, and Pcm is lower, and weldability is better.The poor steel of weldability easily cracks afterwards in welding,, for fear of the generation of crackle, must carry out preheating to steel before welding, and weldability is better, and required preheating temperature is lower, otherwise needs higher preheating temperature.According to the ferrous metallurgy industry standard YB/T 4137-2005 of People's Republic of China (PRC) regulation, the trade mark is the steel grade of Q800CF, and the Pcm value needs lower than 0.28%.Yield strength 900MPa grade steel plate involved in the present invention, microtexture is ultra-fine lath of bainite, has the features such as high tenacity and welding crack sensibility index are low, its welding crack sensibility is lower than 0.25%.
The composition system that the present invention adopts guarantees that steel plate has high strength and low-temperature flexibility, and welding crack sensibility indices P cm≤0.25%, have good welding property simultaneously.
The Composition Design of steel of the present invention is as follows:
C: for the bainitic steel that adopts the TMCP explained hereafter, when carbon content is low, the diffusion phase transformation of bainite ferrite lath is easier to, the bainite ferrite width of sheet that forms is larger, when carbon content is higher, need more carbon atom diffusion during bainitic transformation, the width of bainite ferrite lath reduces.The impelling strength of low-carbon bainite steel is by following controlling factors: pattern and the distribution of the oversaturated carbon content in bainite ferrite, the width of lath of bainite and pattern, participation horse constituent element difficult to understand.Comprehensive several respects factor considers and in conjunction with experimental result, C content of the present invention is controlled to be 0.07～0.14%.
Si:Si does not form carbide, with the solid solution form, is present in steel, hinders the motion of steel Dislocations, improves the intensity of steel.Si can change the free energy that cementite is separated out simultaneously, and the Si of high level can suppress cementite and form.When Si content is higher, can increase the welding crack sensibility index, reduce the welding property of steel.Si content in the present invention is controlled to be 0.25～0.50%.
Mn:Mn enlarges the austenitic area in the carbon iron balance phasor.Mn and Fe can form sosoloid, the Mn that is solid-solubilized in austenite passes through the solute drageffect, reduce the phase driving force of diffusion phase transformation, suppressed on the one hand ferrite transformation, having suppressed on the other hand the end face diffusion control of lath of bainite grows up, refinement lath of bainite, improved intensity and the toughness of steel plate.Usually add the precious alloy elements Mo in steel, suppress the diffusion phase transformation, the refinement lath of bainite.Higher Mn can realize improving intensity by the final tissue of refinement, guarantees that simultaneously steel plate has higher toughness.Add 1.70～2.20% Mn in the present invention, be conducive to form the bainite structure of refinement, make steel have good obdurability.
Nb:Nb has restraining effect to austenite one phase diffusion motion interface, thereby has improved the recrystallization temperature of steel.In two stage rolling processes, higher recrystallization temperature can be after the high temperature section rolling, and recrystallize, crystal grain thinning fully occur austenite crystal.Nb can increase the hardening capacity of steel plate, adds the Nb of certain content can produce the larger steel plate of thickness.Strain inducing can occur and separate out in the carbide of Nb in the subordinate phase operation of rolling, the Nb that separates out (CN) particle has the ability that hinders dislocation motion, improve the dislocation desity in austenite, suppress ferrite transformation, improve the nucleation rate of bainitic transformation, refinement is finally organized, and improves intensity and the toughness of steel plate.Add 0.03～0.10%Nb to control steel plate microtexture and mechanical property in the present invention.
V:V plays the effect of the Carbonitride Precipitation reinforcement of solution strengthening and V in steel.The tiny yield strength that can improve steel plate of separating out of the disperse of V (CN) in drawing process, and not obvious on the impact of toughness.Add 0.03～0.10% V, with the assurance steel plate, higher yield strength is arranged after tempering in the present invention.
Cr:Cr is solid-solubilized in steel, improves the hardening capacity of steel plate.Cr is carbide forming element, can form tiny carbide, improves the intensity of steel plate.Add 0.05～0.50% Cr in the present invention, guarantee intensity and the ballistic work of steel plate.
Ni:Ni in being solid-solubilized in steel, does not form carbide, can reduce ferritic stacking fault energy, improves the low-temperature impact toughness of steel plate.But Ni belongs to the precious alloy element, and content causes the steel plate cost to raise than Gao Shihui, and the market competitiveness descends, and adds 0.20～0.50% Ni in the present invention with the mechanical property that guarantees steel plate and has the market competitiveness.
C in Ti:Ti and steel and N form compound.The formation temperature of TiN is more than 1400 ℃, usually separates out Ti in liquid phase or delta ferrite
4C
2S
2Start to separate out at 1260 ℃, TiC separates out 1050 ℃ of left and right, tiny precipitate meeting pinning crystal boundary, refine austenite size.Ti content in the present invention is controlled at 0.01～0.04%.
Al:Al when comparatively high temps and in steel N form tiny and AlN disperse separates out, inhibiting grain growth, reach crystal grain thinning, improve the purpose of steel toughness at low temperatures.Add the Al crystal grain thinning that is no more than 0.04wt.% in the present invention, improve the toughness of steel plate and guarantee its welding property.
Dislocation and the fault location enrichment of B:B in steel, reduce the crystal boundary energy, suppressed ferritic transformation, promoted the bainite transformation of steel at middle temperature area, increased armor plate strength.When B content was low, not obvious to the facilitation effect of bainitic transformation, the B element was too high, can cause grain-boundary strength significantly to reduce, and formed " boron is crisp " phenomenon.Therefore, in the present invention, the add-on of B is 0.0006～0.0025%.
Adopt the chemical composition of the present invention's design, superiority is to adopt Mn-Cr-Ni-Nb-V composition system, and high strength steel plate is produced in the effect of the alloying element that rationally utilizes.
In the manufacture method of yield strength 900MPa level bainite type high strength steel plate of the present invention, principle and the superiority of rolling and process for cooling are:
Rolling technology
The present invention adopts the two-stage control rolling technology.First stage is out of shape on the non-recrystallization temperature.In distortion, the dislocation of accumulative total can improve steel plate subsurface defect energy, makes steel plate generation dynamic recrystallization, inferior dynamic recrystallization and Static Recrystallization, refine austenite crystal grain.During to 770～860 ℃, start the subordinate phase rolling until temperature after the first stage rolling.The subordinate phase rolling is in the non-recrystallization district of steel plate, and finishing temperature is 760～840 ℃, and lower rolling temperature makes in steel plate and added up a large amount of dislocations.Carbonitride fault generation in place strain inducing is separated out, pinning the motion of dislocation.In follow-up process of cooling, bainite can be at dislocation and fault location forming core, higher dislocation desity refinement final bainite structure.The precipitation strength effect of the carbonitride of small and dispersed and the refined crystalline strengthening effect of refinement lath of bainite, make the higher intensity of having of steel plate and toughness.
Process for cooling
Steel plate enters refrigerating unit after controlled rolling, speed of cooling is 12～45 ℃/s, stops cold temperature and is≤400 ℃.The austenite that has a large amount of dislocations after rolling deformation, quick when cooling, in lesser temps generation bainite transformation.Speed of cooling makes austenite have larger condensate depression faster,, even bainite transformation has larger nuclear driving force, has improved the nucleation rate of bainite transformation.When lesser temps generation bainite transformation, the carbon atom diffusibility weakens, and bainite ferrite sheet end face is grown up and is suppressed, refinement the bainite ferrite lath.It is of the present invention that to stop cold temperature lower, in speed of cooling and lower stopping under cold temperature condition faster, bainite forms with very high nucleation rate and slower coarsening rate,, for the MA constituent element of the austenitic formation small and dispersed that changes is distributed on the bainite matrix, improved intensity and the toughness of steel plate.
Tempering process
Tempering temperature of the present invention is 350～500 ℃.In drawing process, the carbide of V is separated out at fault locations such as dislocation or crystal boundaries.Steel plate is in loading process, and the precipitate of dislocation or grain boundaries has hindered the motion of mobile dislocation, has improved the yield strength of steel plate.In drawing process, the motion of dislocation can occur simultaneously, unlike dislocation is buried in oblivion, and causes steel plate Dislocations density to descend, and tensile strength reduces.Consider the impact of drawing process on yield strength and tensile strength, the present invention is preferred, and tempering temperature is 350～500 ℃, guarantees that steel plate yield strength in drawing process is significantly improved, and that tensile strength descends is not obvious.
The steel billet of composition system of the present invention is at 1080～1280 ℃ of austenitizings, in composition, the carbonitride of Nb and V can be dissolved in austenite more fully, can form tiny carbonitride in the operation of rolling subsequently, the pinning dislocation motion, the refine austenite recrystal grain, finally organize to reach refinement, improve the purpose of steel plate obdurability.Treat temperature after the first stage rolling finishes to the rolling of 770～860 ℃ of beginning subordinate phase on roller-way, finishing temperature is 760～840 ℃.The rolling temperature of subordinate phase is lower, can guarantee that steel plate has corresponding deflection in non-recrystallization district temperature range, in steel plate enrichment a large amount of dislocations.Carbon atom can, to the edge dislocation enrichment, form horse constituent element difficult to understand in cooling phase-change process subsequently.
Steel plate with the speed of 12～45 ℃/s be cooled to≤400 ℃, air cooling after water outlet.Steel plate adopts very fast speed of cooling and lower stops cold temperature, and composition system of the present invention is at lower temperature range generation bainitic transformation, forms the lath of bainite of refinement and along the horse of lath interface distributions constituent element difficult to understand, this type of tissue has the characteristics such as high-strong toughness.In the described system of composition of the present invention, need adopt corresponding speed of cooling and stop cold temperature, just can obtain corresponding mechanical property.Steel plate of the present invention stops after cold to carry out temper, and the steel plate tempering temperature is 350～500 ℃, air cooling after tempering.V separating out in ferrite in drawing process in composition system of the present invention, can produce strengthening effect, improves the yield strength of steel plate, and the tempering time scope can guarantee that the carbonitride in steel plate fully separates out, and realizes the purpose of precipitation strength.
Beneficial effect of the present invention
The present invention, by rational designing chemical composition, substitutes Mo with cheap alloying elements such as Mn, with C, the fine precipitation particles of N chemical combination of V, makes precipitation strength, replace the precipitation strength effect of Cu, alloying element content is few, and raw materials cost is lower, welding crack sensibility is less, need not preheating before weldering.
Steel plate of the present invention need not carry out any extra modified thermal treatment, thereby has simplified manufacturing process, has reduced the manufacturing cost of steel.
The present invention due to composition and technological design reasonable, from implementation result, process system is looser, can in, Plate Steel produces stably manufactured on line.
Steel plate yield strength 〉=900MPa of the present invention, tensile strength 〉=980MPa, Xia Shi Impact energy Ak v (20 ℃) 〉=150J, welding crack sensibility indices P cm≤0.25%, have good welding property.
Description of drawings
Fig. 1 is the stereoscan photograph of the embodiment of the present invention 2 steel plates, and this figure shows the refinement lath of bainite;
Fig. 2 is the transmission electron microscope photo of the embodiment of the present invention 5 steel plates, and this figure shows the lath of bainite substructure of nano level superfine.
Embodiment
Embodiment 1
Pressing the chemical composition shown in table 1 smelts, and be cast into continuously cast bloom or steel ingot, Heating temperature is 1080 ℃, treat after the first stage rolling that temperature is to the rolling of 860 ℃ of beginning subordinate phase, finishing temperature is 840 ℃, and the steel plate speed of cooling is 35 ℃/S, and final temperature is room temperature, tempering temperature is 500 ℃, the rear air cooling of coming out of the stove.
Embodiment 2
Smelt according to the chemical composition shown in table 1, and be cast into continuously cast bloom or steel ingot, Heating temperature is 1280 ℃, treat after first stage rolling rolling that temperature is to the rolling of 770 ℃ of beginning subordinate phase, finishing temperature is 760 ℃, and the steel plate speed of cooling is 12 ℃/S, and final temperature is room temperature, tempering temperature is 450 ℃, the rear air cooling of coming out of the stove.
Embodiment 3
Smelt according to the chemical composition shown in table 1, and be cast into continuously cast bloom or steel ingot, Heating temperature is 1180 ℃, treat after first stage rolling rolling that temperature is to the rolling of 840 ℃ of beginning subordinate phase, finishing temperature is 800 ℃, the steel plate speed of cooling is 45 ℃/S, and final temperature is 400 ℃, and after water outlet, air cooling is to room temperature.Tempering temperature is 500 ℃, the rear air cooling of coming out of the stove.
Embodiment 4
Embodiment is with embodiment 1, and wherein Heating temperature is 1100 ℃, treats temperature after first stage rolling rolling to the rolling of 800 ℃ of beginning subordinate phase, and finishing temperature is 770 ℃, and the steel plate speed of cooling is 25 ℃/S, and final temperature is 350 ℃, and after water outlet, air cooling is to room temperature.Tempering temperature is 400 ℃, the rear air cooling of coming out of the stove.
Embodiment 5
Smelt according to the chemical composition shown in table 1, and be cast into continuously cast bloom or steel ingot, Heating temperature is 1180 ℃, treat temperature after the first stage rolling to the rolling of 790 ℃ of beginning subordinate phase, finishing temperature is 760 ℃, and the steel plate speed of cooling is 30 ℃/S, final temperature is 250 ℃, and after water outlet, air cooling is to room temperature.Tempering temperature is 350 ℃, the rear air cooling of coming out of the stove.
Embodiment 6
Smelt according to the chemical composition shown in table 1, and be cast into continuously cast bloom or steel ingot, Heating temperature is 1200 ℃, treat temperature after the first stage rolling to the rolling of 820 ℃ of beginning subordinate phase, finishing temperature is 800 ℃, and the steel plate speed of cooling is 40 ℃/S, final temperature is 200 ℃, and after water outlet, air cooling is to room temperature.Tempering temperature is 450 ℃, the rear air cooling of coming out of the stove.
The composition of table 1 embodiment, wt%
Test example 1
Yield strength 900MPa level bainite type high strength steel plate to embodiment of the present invention 1-6 carries out Mechanics Performance Testing, and test result is in Table 2.
The mechanical property of the steel plate of table 2 embodiment of the present invention 1-6
As can be seen from Table 1 and Table 2, the Pcm of the yield strength 900MPa level bainite type high strength steel plate that the present invention relates to≤0.25%, yield strength is all greater than 900MPa, and tensile strength is greater than 980MPa, Xia Shi Impact energy Ak v (20 ℃) 〉=150J.
Test example 2
Embodiment 2 and 5 is carried out microtexture research, and stereoscan photograph and transmission electron microscope photo are as shown in Figure of description 1 and 2.Fig. 1 is the stereoscan photograph of embodiment 2 steel plates.As can be seen from the figure, carbide is not only separated out at ultra-fine lath of bainite edge.Fig. 2 is the transmission electron microscope photo of embodiment 5.Lath of bainite is comprised of meticulous nano level lath of bainite.A lot of dislocations of nano level lath of bainite inside provide the dislocations strengthening effect.Ultra-fine lath of bainite makes steel plate have at low temperatures higher toughness.
Claims (3)
1. yield strength 900MPa level bainite type high strength steel plate, it is characterized in that, the chemical composition of percentage ratio meter is by weight: C:0.07～0.14%, Si:0.25～0.50%, Mn:1.70～2.20%, Cr:0.05～0.50%, Ni:0.20～0.50%, Nb:0.03～0.10%, V:0.03～0.10%, Ti:0.01～0.04%, Al:0.02～0.04%, B:0.0006～0.0025%, surplus is Fe and inevitable impurity, welding crack sensibility indices P cm≤0.25%;
Described steel plate is by comprising the method manufacturing of following steps:
Smelting, casting, heating, rolling, cooling and tempering process;
In described heat-processed, Heating temperature is 1080～1280 ℃;
Rolling is divided into first stage and subordinate phase rolling, and described first stage rolling is carried out more than recrystallization temperature, treats temperature after the first stage rolling to the rolling of 770～860 ℃ of beginning subordinate phase on roller-way, and the finishing temperature of subordinate phase rolling is 760～840 ℃;
In described process of cooling, steel plate with the speed of 12～45 ℃/s be cooled to≤400 ℃, air cooling after water outlet;
In described drawing process, tempering temperature is 350～500 ℃, air cooling after tempering.
2. yield strength 900MPa level bainite type high strength steel plate as claimed in claim 1, is characterized in that, air cooling employing stacking or cold bed are cooling.
3. yield strength 900MPa level bainite type high strength steel plate as claimed in claim 2, is characterized in that, yield strength 〉=900MPa, tensile strength 〉=980MPa, the Xia Shi Impact energy Ak v under-20 ℃ are greater than 150J.
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| CN101418416A (en) * | 2007-10-26 | 2009-04-29 | 宝山钢铁股份有限公司 | Low welding crack sensitivity steel plate with yield strength of 800MPa grade and method for producing the same |
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| CN1249006A (en) * | 1997-02-27 | 2000-03-29 | 埃克森生产研究公司 | High-tensile-strength steel and method of manufacturing the same |
| CN1840724A (en) * | 2005-03-30 | 2006-10-04 | 宝山钢铁股份有限公司 | Superhigh strength steel plate with yield strength more than 960Mpa and method for producing same |
| CN1840723A (en) * | 2005-03-30 | 2006-10-04 | 宝山钢铁股份有限公司 | Superhigh strength steel plate with yield strength more than 1100Mpa and method for producing same |
| CN101418416A (en) * | 2007-10-26 | 2009-04-29 | 宝山钢铁股份有限公司 | Low welding crack sensitivity steel plate with yield strength of 800MPa grade and method for producing the same |
| CN101230444A (en) * | 2008-01-02 | 2008-07-30 | 湖南华菱湘潭钢铁有限公司 | High-strength micro-alloy low-carbon bainite steel and production method thereof |
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