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CN107488814A - 800MPa levels analysis of producing hot rolled TRIP and manufacture method based on CSP flows - Google Patents

800MPa levels analysis of producing hot rolled TRIP and manufacture method based on CSP flows Download PDF

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Publication number
CN107488814A
CN107488814A CN201710729121.3A CN201710729121A CN107488814A CN 107488814 A CN107488814 A CN 107488814A CN 201710729121 A CN201710729121 A CN 201710729121A CN 107488814 A CN107488814 A CN 107488814A
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hot rolled
producing hot
rolled trip
level analysis
csp
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CN107488814B (en
Inventor
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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Wuhan Iron and Steel Co Ltd
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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
    • 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
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Metal Rolling (AREA)

Abstract

The invention discloses a kind of 800MPa level analysis of producing hot rolled TRIP based on CSP flows, the chemical element component and its percentage by weight contained is：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 manufacture method of the steel include converter smelting, refining, sheet blank continuous casting, continuous casting billet soaking, high-pressure water descaling, controlled rolling, control cooling, batch.Using the C Si Mn P composition designs of economy, metallographic structure is 50~65% ferrite, 20~40% bainite and 7~15% retained austenite；500~550MPa of yield strength, 800~880MPa of tensile strength, elongation A80For 27~31%, there is good strong plasticity matching.

Description

800MPa levels analysis of producing hot rolled TRIP and manufacture method based on CSP flows
Technical field
The invention belongs to steel hot rolled strip production technical field, and in particular to a kind of 800MPa levels based on CSP flows Analysis of producing hot rolled TRIP and manufacture method.
Background technology
With raising of the people to requirements such as environment, the energy, safety, automobile positive lightweight, high-strength and inexpensive direction Development, it is that automobile tackles this with steel industry 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 somebody with somebody, good combination property and attention.TRIP steel is mainly used to make the baffle plate 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 plates have been used to make on concept chassis About 80 kinds of parts, compared with conventional steel plates, the pts wt manufactured with this steel plate mitigates about 12%, per chassis weight saving about 14kg, economic benefit are obvious.
As the continuous increase of auto industry energy-saving and emission-reduction pressure, its demand to Thin Specs TRIP steel are increasingly urgent.So And this automobile using TRIP steel mainly uses cold rolling+intercritical annealing technique productions, complex process, high energy consumption, cost at present It is high.And slab continuous casting rolling flow is due to higher temperature control precision, ensure that slab temperature in the operation of rolling Uniform stability, has some superiority in the production of Thin Specs 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 Specs analysis of producing hot rolled TRIP and roll, Not only shorten flow but also saved the energy, and meet the development trend of social energy conservation emission reduction, green manufacturing.
The tissue of TRIP steel is typically by 50~60% (vol.) polygonal ferrite, 25~40% carbides-free bayesian Body, 5~15% retained austenite composition, its good plasticity are 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 is：
(1) γ → α transformations first occur for the austenite of finish rolling non-recrystallization after deformation, form more than 50% pro-eutectoid iron Ferritic.Because the solubility of carbon in pro-eutectoid ferrite is relatively low, carbon is ostracised and is enriched with into remaining austenite.Caused ferrite More, the carbon being accordingly enriched with remaining austenite is more.This is the first stage in analysis of producing hot rolled TRIP retained austenite Carbon enrichment.
(2) and then fast cooling to coiling temperature, this stage steel is in bainite transformation constant temperature process, a part of Ovshinsky For body because 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 austenites.
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, is produced with the low height of excellent elongation percentage and strength and ductility product and mechanical property deviation using CSP mode Strength hot rolled TRIP steel.Application publication number is that CN106048176A and CN105821190A Chinese patent is disclosed based on ESP Bar strip continuous casting and rolling flow path production low-carbon, the method for middle carbon analysis of producing hot rolled TRIP, this method is using C-Si-Mn-Mo into setting up separately Meter, is rolled using ESP sheet billet flows, obtains the TRIP steel of different tissues performance, and can solve low-carbon hot-rolling TRIP steel Thickness is overproof end to end.
CSP short-flow production line typically arranges that milling train is to defeated between coiling machine using the milling train of close-coupled Go out roller-way generally shorter (70~90m), and " relatively thin with hot Dai Leng " automobile steel thickness specification, mill speed is very fast, can cause There is no enough middle air cooling times to form the polygonal ferrite of enough ratios (>=50%), then cause remaining austenite In there is no enough carbon, ferrite content and paralympic amount deficiency 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 the metallurgical rule of uniqueness, to C, Mn, Al in composition design Content has certain restriction, but above-mentioned patent does not consider factors above, fails solve the production of CSP short route Line produces the bottleneck problem of analysis of producing hot rolled TRIP.
The content of the invention
Present invention aim to provide a kind of 800MPa levels analysis of producing hot rolled TRIP and manufacture method based on CSP flows, Its metallographic structure is 50~65% ferrite, 20~40% bainite and 7~15% retained austenite, and yield strength It is 800~880MPa for 500~550MPa, tensile strength, elongation A80For 27~31%, there is good strong plasticity matching.
To achieve the above object, the technical solution adopted by the present invention is：800MPa level hot rollings TRIP based on CSP flows Steel, the chemical element component and its percentage by weight contained are：Carbon 0.165~0.20%, silicon 1.40~1.60%, manganese 1.45~ 1.60%th, phosphorus 0.06%~0.08%, sulphur≤0.005%, dissolved aluminum 0.015~0.060%, surplus is for iron and inevitably Impurity.Metallographic structure is 50~65% ferrite, 20~40% bainites and 7~15% retained austenite；Mechanical property： Yield strength is 500~550MPa, 800~880MPa of tensile strength, elongation A80For 27~31%, strength and ductility product reaches More than 22000MPa%.
The chemical composition restriction reason of 800MPa level analysis of producing hot rolled TRIP of the present invention based on CSP flows is as follows：
C (carbon)：C strengthens austenite and strengthens the stability of retained austenite by gap solution strengthening mechanism.First, CSP CSP flows composition design should avoid the C equivalent weight ranges 0.09~0.17% of hypo-peritectic steel, because working as 0.09%<Ceq<0.17%, the tendency of continuous casting crackle, which will occur, to be dramatically increased.This peritectic steel scope should be avoided, when avoiding solidification The linear shrinkage of strand is larger, and surface longitudinal crack is formed in casting process.Secondly, C content is too low, is not enough to form rich carbon Austria Family name's body, C content is too high, can deteriorate welding performance, and C content scope is finally limited according to following carbon equivalent formula：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)：Si main function is that cementite is formed when suppressing bainite isothermal transformation, and the carbon for improving austenite contains Measure so as to improve its stability.In addition, Si can solution strengthening ferrite, there is provided certain intensity；But Si contents are high, easily make It is difficult into de-scaling, increase scale defect occurrence probability, and coating poor-performing, it is final to limit Si content ranges：1.40 ~1.60%, preferably 1.50~1.55%.
Mn (manganese)：Mn increases the quenching degree of steel, stable austenite, suppresses the formation of pearlite, increases remained austenite content, The intensity of ferrite matrix can be also improved by solution strengthening；Mn too high levels, retained austenite overstabilization can be made, be unfavorable for The generation of TRIP effects；>=2.5% Mn contents are easily caused serious banded structure；>=1.6% Mn contents can also give thin plate Base continuous casting belt carrys out certain difficulty, and high Mn can cause thermal conductivity factor to significantly reduce, and causes 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, slab surface crack can be caused when serious.It is final to limit Mn content ranges：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 effectively to be prevented The precipitation of cementite during bainite isothermal transformation, be advantageous to the reservation of metastable state austenite, while P also can be very effective solid Molten intensified element.When P content it is too high (>0.25%), phosphide Fe can be formed in crystal boundary3P, performance is adversely affected, most P content scope 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 advantageous to crystal grain thinning.
S (sulphur)：S influences the degree of purity and toughness of steel as the harmful element in steel, by S contents be defined to S≤ 0.005%
A kind of manufacture method of the 800MPa level analysis of producing hot rolled TRIP as described above based on CSP flows is also provided, including with Lower step：
1) smelt
Molten steel is formed by the composition and percentage by weight are well mixed, uses pneumatic steelmaking-LF-RH techniques during smelting, In pneumatic steelmaking using S contents relatively low 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 into Divide and meet that 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 Composition preferred scope is：C：0.17~0.19%, Si：1.50~1.55%；Mn：1.50~1.56%；
2) continuous casting
Bag molten steel overheat is 15~20 DEG C in being controlled during continuous casting, slab thickness is 52~55mm, casting speed be 4.0~ 5.5m/min, continuous-casting sheet billet is formed, slab quality is ensured 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-up temperature is T2 =1120~1150 DEG C, heating cycle is shown in accompanying drawing 1；
4) de-scaling
Continuous-casting sheet billet, which goes out before soaking pit feed mill, carries out high-pressure water descaling, control de-scaling water pressure be 280~ 420bar；
5) roll
The percentage pass reduction of finishing rolling control first 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 frame between the first passage and second time, de-scaling water pressure is 200~280bar；
Finishing temperature is controlled at 800~820 DEG C；
6) cool down
680~700 DEG C, 4~8s of air cooling are cooled to 50~90 DEG C/s cooling rate, it is then cold with >=100 DEG C/s cooling rate But 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 is controlled：O2Content 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 level analysis of producing hot rolled TRIP manufacture methods provided by the invention based on CSP flows, control 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 stove≤2.0%, and H2During O steam content ＞ 5.0%, between stove life iron scale and matrix Adhesion is relatively low, is easy to the de-scaling containing high Si steel.
(2) iron scale of second segment low-temperature epitaxy is using the two-part mode of heating of low temperature after first high temperature, reason It is good with the iron scale tack of outer layer hot stage oxidation generation, through-wall crack is easily formed in de-scaling and is shelled from substrate Fall, be not easy residual oxidization iron sheet and see accompanying drawing 2 in surface, specific mechanism.
(3) controlling finishing temperature, this temperature range can guarantee that carries out finish to gauge in austenite one phase area at 800~820 DEG C, It can make the austenite crystal of finish rolling end frame more tiny (8~12 μm) by relatively low temperature, ferritic forming core can be accelerated. In addition, can to reduce the time that mill speed makes strip be run in roller repairing section longer for low temperature finish to gauge, you can ensures longer Air cooling time.
(4) 680~700 DEG C of medium temperatures are cooled to 50~90 DEG C/s cooling rate after rolling, 4~8s of air cooling time, passed through Fast speed is cooled to ferritic transformation curve nose temperature and starts ferritic transformation, and ratio enough is generated by isothermal in this temperature The ferrite of example, cools down route and curve is shown in accompanying drawing 3.
(5) then with >=100 DEG C/s cooling rate be cooled to 380~400 DEG C batch start bainite isothermal transformation, using compared with Fast cooling velocity is formed to suppress pearlite, and coiling temperature is too high, and the residual austenite of formation is known from experience in Slow cooling process Middle decomposition, reduce its stability.
Compared with prior art, the present invention has advantages below：
(1) 800MPa levels analysis of producing hot rolled TRIP provided by the invention is using economic C-Si-Mn-P composition designs, 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 A80For 27~31%, there is good strong plasticity matching.
(2) by using the two-part soaking pit mode of heating of low temperature after first high temperature, change iron scale attachment and peel off And mechanism, the occurrence probability that iron scale remains is reduced, improves the surface quality of coil of strip.
(3) CSP CSP flows ensure that slab in the operation of rolling based on its higher temperature control precision The uniform stability of middle temperature, significantly decreases aberrations in property of the strip on width and length direction, production it is thin Size hot-rolled TRIP steel is suitable with Cold-Rolled TRIP Steel performance, can be achieved " with hot Dai Leng ".
(4) it is heat treated after eliminating cold rolling using CSP CSP flows production analysis of producing hot rolled TRIP and roll Journey, shorten flow and saved the energy, meet the megatrend of energy-saving and emission-reduction, green manufacturing.
Brief description of the drawings
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 in soaking stove heat rear oxidation iron sheet de-scaling mechanism figure；
Fig. 3 is the cooling technique route map used in analysis of producing hot rolled TRIP manufacture method of the present invention.
Embodiment
With reference to embodiment, the present invention is described in further detail, is easy to more clearly understand the present invention, but it Not to the present invention form limit.
Analysis of producing hot rolled TRIP of the present invention includes converter using converter-CSP CSP flows production, specific steps Smelting, refining, sheet blank continuous casting, continuous casting billet soaking, high-pressure water descaling, controlled rolling, control are cooled down, batched.
Steel use pneumatic steelmaking-LF-RH techniques when smelting, and molten steel depth desulfurization pretreatment is used in pneumatic steelmaking, Ensure S contents relatively low in steel, carry 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 composition as shown in table 1 below numbering A-C is obtained.Table 1 Middle numbering D, E is comparative example, and numbering E is the 800MP level cold rollings using conventional hot rolling+cold rolling+intercritical annealing technique productions TRIP steel.
Table 1
Bag molten steel overheat is at 15~20 DEG C in being controlled during continuous casting, and slab thickness is 52~55mm, casting speed 4.0~ 5.5m/min, slab quality is ensured by suitable molten steel overheat and higher Casting speed.
Strand 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 contents control≤0.5%；
860~880 DEG C of soaking pit charging temperature, bringing-up section temperature T1=1200~1220 DEG C, soaking zone heating-up temperature is T2 =1120~1150 DEG C, heating cycle is shown in accompanying drawing 1.
Strand carries out high-pressure water descaling, 280~420bar of control de-scaling water pressure before going out soaking pit feed mill.
The percentage pass reduction of finishing rolling control first is：50~65%, the second percentage pass reduction is：50~60%, extreme trace time pressure Lower rate is：10~15%；Controlled rolling speed is in 5.5~10m/s；Carry out removing between frame 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/s cooling rate is cooled to 680~700 DEG C, 4~8s of air cooling, being then cooled to 380~400 DEG C with >=100 DEG C/s cooling rate enters 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 compositions altogether, is high P steel, For comparative example D compared with example B, P content is relatively low, 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 middle 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 with the example coil of strip of different middle air cooling times reach TRIP steel It is required that：For ratio of ferrite from 50% to 65%, retained austenite ratio has relatively low centre from 7.5~14.2%, example The example ferrite and retained austenite ratio of air cooling time are relatively lower slightly, the example B-4 containing P and the comparative example without 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 A80For 27.4~30.2%, strength and ductility product reaches more than 22646MPa%, Except yield strength ratio is with high using the comparative example E of conventional hot rolling+cold rolling+intercritical annealing technique, other properties are basic Quite.
Table 3
Note：F- ferrites, B- bainites, γ-retained austenite..
It is 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 manufacture method are bases In CSP short routes, because the different process route of TSCR bar strip continuous casting and rolling flow paths has consistent technique thinking, the present invention Application of the described analysis of producing hot rolled TRIP and its manufacture method in other short route producing lines such as ESP, FTSR ought to be protected in the present invention Within the scope of.

Claims (8)

  1. A kind of 1. 800MPa level analysis of producing hot rolled TRIP based on CSP flows, it is characterised in that：The chemical element component that contains and its again Measuring percentage is：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.
  2. 2. the 800MPa level analysis of producing hot rolled TRIP based on CSP flows according to claim 1, it is characterised in that：The weight of the carbon It is 0.17~0.19% to measure percentage.
  3. 3. the 800MPa level analysis of producing hot rolled TRIP based on CSP flows according to claim 1, it is characterised in that：The weight of the silicon It is 1.50~1.55% to measure percentage.
  4. 4. the 800MPa level analysis of producing hot rolled TRIP based on CSP flows according to claim 1, it is characterised in that：The weight of the manganese It is 1.50~1.56% to measure percentage.
  5. 5. a kind of manufacture method of the 800MPa level analysis of producing hot rolled TRIP based on CSP flows as claimed in claim 1, its feature exist In：Comprise the following steps：
    1) smelt
    Form molten steel by the composition and percentage by weight are well mixed, use pneumatic steelmaking-LF-RH techniques during smelting, turn Molten steel depth desulfurization pretreatment is used when stove is made steel, uses RH vacuum system refined molten steels again；
    2) continuous casting
    Bag molten steel overheat is 15~20 DEG C in being controlled during continuous casting, slab thickness is 52~55mm, casting speed be 4.0~ 5.5m/min, form 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-up 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, and it is 280~420bar to control de-scaling water pressure；
    5) roll
    The percentage pass reduction of finishing rolling control first is 50~65%, and the second percentage pass reduction is 50~60%, and last percentage pass reduction is 10~15%, and controlled rolling speed is 5.5~10m/s；
    The de-scaling between progress frame between the first passage and second time, de-scaling water pressure is 200~280bar；
    Finishing temperature is controlled at 800~820 DEG C；
    6) cool down
    680~700 DEG C are cooled to 50~90 DEG C/s cooling rate, 4~8s of air cooling, is then cooled to >=100 DEG C/s cooling rate 380~400 DEG C are batched.
  6. 6. the manufacture method of the 800MPa level analysis of producing hot rolled TRIP based on CSP flows according to claim 5, 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.
  7. 7. the manufacture method of the 800MPa level analysis of producing hot rolled TRIP based on CSP flows, its feature exist according to claim 5 or 6 In：In the step 3), soaking furnace atmosphere is controlled：O2Content control 3.0~5.0%, vapour content control≤ 0.5%.
  8. 8. the manufacture method of the 800MPa level analysis of producing hot rolled TRIP based on CSP flows, its feature exist according to claim 5 or 6 In：In the step 6), the type of cooling is ultrafast cold, section cooling, Water-Curta in Cooling, encryption cooling or its combination.
CN201710729121.3A 2017-08-23 2017-08-23 800MPa grade analysis of producing hot rolled TRIP and manufacturing method based on CSP process Active CN107488814B (en)

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