CN107488814B - 800MPa grade analysis of producing hot rolled TRIP and manufacturing method based on CSP process - Google Patents

800MPa grade analysis of producing hot rolled TRIP and manufacturing method based on CSP process Download PDF

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CN107488814B
CN107488814B CN201710729121.3A CN201710729121A CN107488814B CN 107488814 B CN107488814 B CN 107488814B CN 201710729121 A CN201710729121 A CN 201710729121A CN 107488814 B CN107488814 B CN 107488814B
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hot rolled
cooling
producing hot
steel
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CN107488814A (en
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刘洋
毛新平
汪水泽
徐进桥
甘晓龙
孙宜强
蔡珍
刘志勇
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Wuhan Iron and Steel Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/02Ferrous alloys, e.g. steel alloys containing silicon
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226Hot rolling
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/002Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/04Ferrous alloys, e.g. steel alloys containing manganese
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/06Ferrous alloys, e.g. steel alloys containing aluminium
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/001Austenite
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/002Bainite
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/005Ferrite

Abstract

The invention discloses a kind of 800MPa grade analysis of producing hot rolled TRIP based on CSP process, the chemical element component and its weight percent contained are as follows: carbon 0.165~0.20%, silicon 1.40~1.60%, manganese 1.45~1.60%, phosphorus 0.06%~0.08%, sulphur≤0.005%, dissolved aluminum 0.015~0.060%, surplus are iron and inevitable impurity.The manufacturing method of the steel includes converter smelting, refining, sheet blank continuous casting, continuous casting billet soaking, high-pressure water descaling, controlled rolling, control is cooling, batches.Designed using economic C-Si-Mn-P ingredient, metallographic structure be 50~65% ferrite, 20~40% bainite and 7~15% retained austenite;500~550MPa of yield strength, 800~880MPa of tensile strength, elongation A80It is 27~31%, there is good strong plasticity matching.

Description

800MPa grade analysis of producing hot rolled TRIP and manufacturing method based on CSP process
Technical field
The invention belongs to steel hot rolled strip production technical fields, and in particular to a kind of 800MPa grade based on CSP process Analysis of producing hot rolled TRIP and manufacturing method.
Background technique
Raising with people to requirements such as environment, the energy, safety, automobile positive lightweight, high-strength and inexpensive direction Development is that automobile and steel industry cope with this using AHSS (Advanced high-strength steels, advanced high-strength steel) The major measure that kind trend is taken jointly.TRIP steel (phase change induction plasticity steel) has high intensity and elongation percentage in AHSS Match, good comprehensive performance and have attracted much attention.TRIP steel is mainly used to make the baffle of automobile, arrangements for automotive doors fender rod, insurance Thick stick, vehicle chassis component, rim for automobile wheel and car door impact beam etc..In Japan, TRIP steel plate has been used on production concept chassis About 80 kinds of parts mitigate about 12% with the pts wt that this steel plate manufactures, every trolley weight saving is about compared with conventional steel plates 14kg, economic benefit are obvious.
With the continuous increase of auto industry energy-saving and emission-reduction pressure, the demand to thin gauge TRIP steel is increasingly urgent to.So And this automobile TRIP steel mainly uses cold rolling+intercritical annealing technique production, complex process, energy consumption height, cost at present It is high.And slab continuous casting rolling process is due to temperature control precision with higher, ensure that slab temperature during the rolling process Uniform stability, has some superiority in the production of thin gauge automobile high-strength steel, and portioned product can be realized " with hot Dai Leng ". Therefore, the heat treatment process after eliminating cold rolling using bar strip continuous casting and rolling flow path production thin gauge analysis of producing hot rolled TRIP and roll, Not only it had shortened process but also had saved the energy, and met the development trend of social energy conservation emission reduction, green manufacturing.
The tissue of TRIP steel is generally by the polygonal ferrite of 50~60% (vol.), 25~40% carbides-free bayesian Body, 5~15% retained austenite composition, good plasticity is by the strain-induced phase transformation of retained austenite in tissue and polygon The coefficient result of shape ferrite.Thus the polygonal ferrite with proper ratio and retained austenite are that TRIP steel obtains The precondition of good plasticity.
The structural transformation principle of analysis of producing hot rolled TRIP are as follows:
(1) γ → α transformation first occurs for the austenite of finish rolling non-recrystallization after deforming, and forms 50% or more pro-eutectoid iron Ferritic.Since the solubility of carbon in pro-eutectoid ferrite is lower, carbon is ostracised and is enriched with into remaining austenite.The ferrite of generation More, the carbon being accordingly enriched in remaining austenite is more.This is the first stage in analysis of producing hot rolled TRIP retained austenite Carbon enrichment.
(2) then for fast cooling to coiling temperature, this stage steel is in bainite transformation constant temperature process, a part of Ovshinsky For body since the element interactions such as Si are changed into carbide-free Bainite, remaining austenite remains further enriched carbon to room Temperature.This is the carbon enrichment of second stage in TRIP steel retained austenite.
The Chinese patent that grant number is CN103249847B disclose manufacture tensile strength grade be 590MPa, machinability The method of excellent and small mechanical property deviation high strength cold-rolled/analysis of producing hot rolled TRIP, this method is tied to form using C-Si-Mn to be set up separately Meter, the height low with excellent elongation percentage and strength and ductility product and mechanical property deviation is produced using thin slab continuous casting and rolling mode Strength hot rolled TRIP steel.Application publication number is that the Chinese patent of CN106048176A and CN105821190A is disclosed based on ESP The method that bar strip continuous casting and rolling flow path produces low-carbon, middle carbon analysis of producing hot rolled TRIP, this method is using C-Si-Mn-Mo at setting up separately Meter, is rolled using ESP sheet billet process, obtains the TRIP steel of different tissues performance, and can solve low-carbon hot-rolling TRIP steel Thickness is overproof end to end.
Thin slab continuous casting and rolling short-flow production line generally uses the milling train of close-coupled to arrange, milling train is to defeated between coiling machine Roller-way is usually shorter (70~90m) out, and the automobile steel thickness specification of " with hot Dai Leng " is relatively thin, and mill speed is very fast, will lead to There is no enough intermediate air cooling times to form the polygonal ferrite of enough ratios (>=50%), then leads to remaining austenite In there is no enough carbon, ferrite content and paralympic amount are insufficient in the final tissue of formation, and form a certain amount of martensite, deteriorate The structure property of TRIP steel.And bar strip continuous casting and rolling flow path has unique metallurgy rule, to C, Mn, Al in ingredient design Content has certain restriction, but above-mentioned patent does not consider factors above, not can solve the production of thin slab continuous casting and rolling short route The bottleneck problem of line production analysis of producing hot rolled TRIP.
Summary of the invention
Present invention aim to provide a kind of 800MPa grade analysis of producing hot rolled TRIP and manufacturing method based on CSP process, Its metallographic structure be 50~65% ferrite, 20~40% bainite and 7~15% retained austenite, and yield strength It is 800~880MPa for 500~550MPa, tensile strength, elongation A80It is 27~31%, there is good strong plasticity matching.
To achieve the above object, the technical solution adopted by the present invention is that: the 800MPa grade hot rolling TRIP based on CSP process Steel, the chemical element component contained and its weight percent are as follows: carbon 0.165~0.20%, silicon 1.40~1.60%, manganese 1.45~ 1.60%, phosphorus 0.06%~0.08%, sulphur≤0.005%, dissolved aluminum 0.015~0.060%, surplus is for iron and inevitably Impurity.Metallographic structure be 50~65% ferrite, 20~40% bainites and 7~15% retained austenite;Mechanical property: Yield strength is 500~550MPa, 800~880MPa of tensile strength, elongation A80It is 27~31%, strength and ductility product reaches 22000MPa% or more.
The chemical component restriction reason of 800MPa grade analysis of producing hot rolled TRIP of the present invention based on CSP process is as follows:
C (carbon): C is strengthened austenite by gap solution strengthening mechanism and enhances the stability of retained austenite.Firstly, Thin slab continuous casting and rolling CSP process ingredient designs the C equivalent weight range 0.09~0.17% that should avoid hypo-peritectic steel, because working as 0.09% < Ceq < 0.17%, the tendency that continuous casting crackle occurs will dramatically increase.This peritectic steel range should be avoided, when avoiding solidification The linear shrinkage of slab is larger, and surface longitudinal crack is formed in continuous casting process.Secondly, C content is too low, it is difficult to understand to be not enough to be formed rich carbon Family name's body, C content is excessively high, can deteriorate welding performance, finally limits C content range according to following carbon equivalent formulas: 0.165~ 0.20%, preferably 0.17~0.19%.
Ceq (carbon equivalent)=[C]+0.0146 [Mn] -0.0027 [Si] -0.0385 [Al]2–0.0568[Al]+0.8297 [S]+0.0136[Mn][Si]–0.0104[Si][Al]+0.0026[Si][Al]2+0.0134[Mn][Al]+0.0031[Mn] [Al]2
Si (silicon): the main function of Si is that cementite is formed when inhibiting bainite isothermal transformation, and the carbon for improving austenite contains Amount is to improve its stability.In addition, Si can solution strengthening ferrite, certain intensity is provided;But Si content is high, is easy to make At de-scaling difficulty, increase scale defect occurrence probability, and coating performance is poor, the final Si content range that limits: 1.40 ~1.60%, preferably 1.50~1.55%.
Mn (manganese): Mn increases the harden ability of steel, and stable austenite inhibits the formation of pearlite, increases remained austenite content, The intensity of ferrite matrix can be also improved by solution strengthening;Mn too high levels can make retained austenite overstabilization, be unfavorable for The generation of TRIP effect;>=2.5% Mn content easily leads to serious banded structure;>=1.6% Mn content can also give thin plate Base continuous casting belt carrys out certain difficulty, and high Mn will cause thermal coefficient significant decrease, cause casting blank shell internal-external temperature difference larger;While by Higher in its linear expansion coefficient, volume contraction is larger during steel billet temperature drop, thus is formed during slab cooling larger Internal stress, will cause slab surface crack when serious.The final Mn content range that limits: 1.45~1.60%, preferably 1.50 ~1.56%.
P (phosphorus): P can accelerate pro-eutectoid ferrite to be formed, and a small amount of P (P≤0.10%) is added in steel can effectively prevent The precipitation of cementite when bainite isothermal transformation is conducive to the reservation of metastable state austenite, while P can be also very effective admittedly Molten intensified element.When P content is excessively high (> 0.25%), meeting forms phosphide Fe in crystal boundary3P adversely affects performance, most P content range 0.06~0.08% is limited eventually.
Als (dissolved aluminum): Al is the deoxidier of the addition in steel, and 0.015~0.06% Al is conducive to refine crystal grain.
S (sulphur): S, as the harmful element in steel, influences the degree of purity and toughness of steel, by S content be limited to S≤ 0.005%
A kind of manufacturing method of 800MPa grade analysis of producing hot rolled TRIP as described above based on CSP process is also provided, including with Lower step:
1) it smelts
It being uniformly mixed by the ingredient and weight percent and forms molten steel, when smelting, uses pneumatic steelmaking-LF-RH technique, In pneumatic steelmaking using lower S content in molten steel depth desulfurization pretreatment, guarantee steel, deoxidation is carried out using calcium and magnesium deoxidier, The oxygen and aluminium in molten steel are reduced, and improves the form, size and distribution of field trash;After RH application of vacuum, in steel chemistry at Point meeting mass percent (wt%) exists: C:0.165~0.20%, Si:1.40~1.60%, Mn:1.45~1.60%, P: 0.06~0.08%, S≤0.005%, Als:0.015~0.060%, remaining is iron and inevitable impurity;Primary chemical Ingredient preferred scope are as follows: C:0.17~0.19%, Si:1.50~1.55%;Mn:1.50~1.56%;
2) continuous casting
Baotou steel water superheat is 15~20 DEG C in control when continuous casting, slab thickness is 52~55mm, drawing speed be 4.0~ 5.5m/min forms continuous-casting sheet billet, guarantees slab quality by suitable molten steel overheat and higher Casting speed;
3) continuous-casting sheet billet soaking
860~880 DEG C of soaking pit charging temperature, bringing-up section temperature T1=1200~1220 DEG C, soaking zone heating temperature is T2 =1120~1150 DEG C, heating cycle is shown in attached drawing 1;
4) de-scaling
Continuous-casting sheet billet, which goes out before soaking pit feed mill, carries out high-pressure water descaling, and control de-scaling water pressure is 280~ 420bar;
5) it rolls
The first percentage pass reduction of finishing rolling control is 50~65%, and the second percentage pass reduction is 50~60%, extreme trace time pressure Rate is 10~15%, and controlled rolling speed is 5.5~10m/s;
The de-scaling between progress rack between the first passage and second time, de-scaling water pressure are 200~280bar;
Finishing temperature is controlled at 800~820 DEG C;
6) cooling
680~700 DEG C, air-cooled 4~8s are cooled to the cooling rate of 50~90 DEG C/s, it is then cold with the cooling rate of >=100 DEG C/s But it is batched to 380~400 DEG C.
Further, the continuous-casting sheet billet, which enters, carries out de-scaling processing before soaking pit, de-scaling water pressure 300~ 400bar。
Further, in the step 3), soaking furnace atmosphere: O is controlled2Content is controlled in 3.0~5.0%, water vapour Content control≤0.5%.
Further, in the step 6), the type of cooling is ultrafast cold, section cooling, Water-Curta in Cooling, encryption cools down or it Combination.
800MPa grade analysis of producing hot rolled TRIP manufacturing method provided by the invention based on CSP process, controls each manufacturing step The reasons why it is as described below:
(1) soaking furnace atmosphere, O are controlled2Amount control is in 3.0~5.0%, H2O steam content≤0.5%;
When oxygen content in furnace≤2.0%, and H2When O steam content > 5.0%, between the raw iron scale of furnace and matrix Binding force is lower, is easy to the de-scaling containing high Si steel.
(2) using the two-part heating method of low temperature after first high temperature, reason is the iron scale of second segment low-temperature epitaxy The iron scale adhesion generated with the oxidation of outer layer hot stage is good, and in de-scaling, through-wall crack easy to form is shelled from substrate It falls, is not easy residual oxidization iron sheet on surface, specific mechanism is shown in attached drawing 2.
(3) for control finishing temperature at 800~820 DEG C, this temperature range, which can guarantee, carries out finish to gauge in austenite one phase area, The austenite grain of finish rolling end rack can be kept more tiny (8~12 μm) by lower temperature, ferritic forming core can be accelerated. In addition, can to reduce the time that mill speed runs strip in roller repairing section longer for low temperature finish to gauge, that is, can guarantee longer Air cooling time.
(4) 680~700 DEG C of medium temperatures are cooled to the cooling rate of 50~90 DEG C/s after rolling, 4~8s of air cooling time passes through Fast speed is cooled to ferritic transformation curve nose temperature and starts ferritic transformation, generates ratio enough by isothermal in this temperature The ferrite of example, cooling route and curve are shown in attached drawing 3.
(5) then with the cooling rate of >=100 DEG C/s be cooled to 380~400 DEG C batch start bainite isothermal transformation, using compared with Fast cooling velocity is to inhibit pearlite to be formed, and coiling temperature is excessively high, and the residual austenite of formation is known from experience in Slow cooling process Middle decomposition reduces its stability.
Compared with prior art, the invention has the following advantages that
(1) 800MPa grades of analysis of producing hot rolled TRIP provided by the invention is using economic C-Si-Mn-P ingredient design, metallographic structure For 50~65% ferrite, 20~40% bainite and 7~15% retained austenite;500~550MPa of yield strength, 800~880MPa of tensile strength, elongation A80It is 27~31%, there is good strong plasticity matching.
(2) by using the two-part soaking pit heating method of low temperature after first high temperature, change iron scale attachment and peel off And mechanism, the remaining occurrence probability of iron scale is reduced, the surface quality of coil of strip is improved.
(3) thin slab continuous casting and rolling CSP process is based on its higher temperature control precision, ensure that slab in the operation of rolling The uniform stability of middle temperature, reduces aberrations in property of the strip in width direction and length direction significantly, production it is thin Size hot-rolled TRIP steel and Cold-Rolled TRIP Steel performance are quite, it can be achieved that " with hot Dai Leng ".
(4) heat treated after eliminating cold rolling using thin slab continuous casting and rolling CSP process production analysis of producing hot rolled TRIP and roll Journey shortens process and has saved the energy, meets the megatrend of energy-saving and emission-reduction, green manufacturing.
Detailed description of the invention
Fig. 1 is the heating cycle that analysis of producing hot rolled TRIP of the present invention uses in soaking pit;
Fig. 2 is analysis of producing hot rolled TRIP of the present invention iron scale de-scaling mechanism figure after soaking stove heating;
Fig. 3 is the cooling technique route map used in analysis of producing hot rolled TRIP manufacturing method of the present invention.
Specific embodiment
Below with reference to embodiment, the present invention is described in further detail, convenient for more clearly understanding the present invention, but it Limiting the invention.
For analysis of producing hot rolled TRIP of the present invention using converter-thin slab continuous casting and rolling CSP process production, specific steps include converter Smelting, refining, sheet blank continuous casting, continuous casting billet soaking, high-pressure water descaling, controlled rolling, control is cooling, batches.
Steel use pneumatic steelmaking-LF-RH technique when smelting, and molten steel depth desulfurization pretreatment is used in pneumatic steelmaking, Guarantee lower S content in steel, carries out deoxidation using calcium and magnesium deoxidier, reduce oxygen and aluminium in molten steel, and improve field trash Form, size and distribution.After RH application of vacuum, the molten steel with the chemical component as shown in the following table 1 number A-C is obtained.Table 1 Middle number D, E is comparative example, and number E is using conventional hot rolling+cold rolling+intercritical annealing technique production 800MP grade cold rolling TRIP steel.
Table 1
For baotou steel water superheat at 15~20 DEG C, slab thickness is 52~55mm in control when continuous casting, drawing speed 4.0~ 5.5m/min guarantees slab quality by suitable molten steel overheat and higher Casting speed.
Slab carries out de-scaling processing before entering soaking pit, and de-scaling water pressure is in 300~400bar;
Control soaking furnace atmosphere, O2Content is controlled in 3.0~5.0%, H2O steam content control≤0.5%;
860~880 DEG C of soaking pit charging temperature, bringing-up section temperature T1=1200~1220 DEG C, soaking zone heating temperature is T2 =1120~1150 DEG C, heating cycle is shown in attached drawing 1.
Slab carries out high-pressure water descaling before going out soaking pit feed mill, control 280~420bar of de-scaling water pressure.
The first percentage pass reduction of finishing rolling control are as follows: 50~65%, the second percentage pass reduction are as follows: 50~60%, extreme trace time pressure Lower rate are as follows: 10~15%;Controlled rolling speed is in 5.5~10m/s;It carries out removing between rack between the first passage and second time Squama, de-scaling water pressure are 200~280bar;Finishing temperature is controlled at 800~820 DEG C.Enter cooling platform after rolling, with 50~90 DEG C/cooling rate of s is cooled to 680~700 DEG C, air-cooled 4~8s, then with the cooling rate of >=100 DEG C/s be cooled to 380~400 DEG C into Row batches.The type of cooling is section cooling mode.
The finish rolling of example and cooling main technologic parameters are shown in Table 2, and example A~C uses 3 ingredients altogether, are high P steel, For comparative example D compared with example B, P content is lower, and other compositions are essentially identical, and trimmed size is from 1.0~2.8mm, different-thickness Gauge steel rolling speed interval is from 5.5m/s to 9.6m/s, so as to cause different intermediate air cooling times, from 4.1s~7.2s.
Table 2
The tissue and mechanical property of example and comparative example are shown in Table 3, it can be seen that pass through optimizing components and low temperature finish to gauge work Skill, the ratio of ferrite and retained austenite ratio of the example coil of strip with different intermediate air cooling times reach TRIP steel It is required that: for ratio of ferrite from 50% to 65%, retained austenite ratio has lower centre from 7.5~14.2%, example The example ferrite and retained austenite ratio of air cooling time are relatively slightly lower, the example B-4 containing P and the comparative example for being free of P D-1 is compared, and other compositions content is essentially identical, but ferrite and retained austenite improve.Yield strength 510~ 542MPa, 820~852MPa of tensile strength, elongation A80It is 27.4~30.2%, strength and ductility product reaches 22646MPa% or more, In addition to yield strength ratio and using the comparative example E high of conventional hot rolling+cold rolling+intercritical annealing technique, other properties are basic Quite.
Table 3
Note: F- ferrite, B- bainite, γ-retained austenite..
It should be pointed out that only the invention will be further described for above-described embodiment, it is other non-with being made according to the present invention Essence modification or adjustment still fall within protection scope of the present invention.Analysis of producing hot rolled TRIP as described in the present invention and its manufacturing method are bases In CSP short route, since the different process route of TSCR bar strip continuous casting and rolling flow path has consistent technique thinking, the present invention Application of the analysis of producing hot rolled TRIP and its manufacturing method in other short route producing lines such as ESP, FTSR ought to be protected in the present invention Within the scope of.

Claims (4)

1. a kind of manufacturing method of the 800MPa grade analysis of producing hot rolled TRIP based on CSP process, it is characterised in that: the following steps are included:
1) it smelts
It is uniformly mixed by the ingredient and weight percent and forms molten steel, when smelting uses pneumatic steelmaking-LF-RH technique, is turning Using molten steel depth desulfurization pretreatment, again using RH vacuum system refined molten steel when furnace is made steel;
2) continuous casting
Baotou steel water superheat is 15~20 DEG C in control when continuous casting, slab thickness is 52~55mm, drawing speed be 4.0~ 5.5m/min forms continuous-casting sheet billet;
3) continuous-casting sheet billet soaking
860~880 DEG C of soaking pit charging temperature, bringing-up section temperature T1=1200~1220 DEG C, soaking zone heating temperature is T2= 1120~1150 DEG C;
4) de-scaling
Continuous-casting sheet billet carries out high-pressure water descaling before going out soaking pit feed mill, control de-scaling water pressure is 280~420bar;
5) it rolls
The first percentage pass reduction of finishing rolling control is 50~65%, and the second percentage pass reduction is 50~60%, and final reduction rate is 10~15%, and controlled rolling speed is 5.5~10m/s;
The de-scaling between progress rack between the first passage and second time, de-scaling water pressure are 200~280bar;
Finishing temperature is controlled at 800~820 DEG C;
6) cooling
680~700 DEG C are cooled to the cooling rate of 50~90 DEG C/s, then air-cooled 4~8s is cooled to the cooling rate of >=100 DEG C/s 380~400 DEG C are batched;
Wherein, the chemical element component and its weight percent that the 800MPa grade analysis of producing hot rolled TRIP based on CSP process contains are as follows: carbon 0.165~0.20%, silicon 1.40~1.60%, manganese 1.45~1.60%, phosphorus 0.06%~0.08%, sulphur≤0.005%, acid are molten Aluminium 0.015~0.060%, surplus are iron and inevitable impurity.
2. the manufacturing method of the 800MPa grade analysis of producing hot rolled TRIP according to claim 1 based on CSP process, it is characterised in that: The continuous-casting sheet billet carries out de-scaling processing before entering soaking pit, and de-scaling water pressure is in 300~400bar.
3. the manufacturing method of the 800MPa grade analysis of producing hot rolled TRIP according to claim 1 or claim 2 based on CSP process, feature exist In: in the step 3), control soaking furnace atmosphere: O2Content control 3.0~5.0%, vapour content control≤ 0.5%.
4. the manufacturing method of the 800MPa grade analysis of producing hot rolled TRIP according to claim 1 or claim 2 based on CSP process, feature exist In: in the step 6), the type of cooling is ultrafast cold, section cooling, Water-Curta in Cooling, encryption cooling or combinations thereof mode.
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