CN107904478A - Reduce the manufacture method of cold rolling low-alloy high-strength steel ferritic-pearlitic type segregation - Google Patents

Reduce the manufacture method of cold rolling low-alloy high-strength steel ferritic-pearlitic type segregation Download PDF

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Publication number
CN107904478A
CN107904478A CN201710949347.4A CN201710949347A CN107904478A CN 107904478 A CN107904478 A CN 107904478A CN 201710949347 A CN201710949347 A CN 201710949347A CN 107904478 A CN107904478 A CN 107904478A
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China
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cold rolling
temperature
alloy high
strength steel
segregation
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CN201710949347.4A
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Chinese (zh)
Inventor
王宝川
贾岳
李亚东
李涛
金磊
郑学斌
韩龙帅
李少博
姚野
杨建炜
胡开广
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Shougang Group Co Ltd
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Shougang Group Co Ltd
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Priority to CN201710949347.4A priority Critical patent/CN107904478A/en
Publication of CN107904478A publication Critical patent/CN107904478A/en
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • 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
    • 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
    • C21D8/0236—Cold 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
    • C22C38/02—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
    • 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
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/40—Plates; Strips

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

Abstract

A kind of manufacture method for reducing the segregation of cold rolling low-alloy high-strength steel ferritic-pearlitic type, belongs to smelting iron and steel and Controlled Rolling And Controlled Cooling field.The constituent mass percentage of low-alloy high-strength steel is C:0.045~0.075%, Mn:0.85~1.1%Mn, Si:0.15~0.25%, Alt:0.025~0.055%, Nb:0.03~0.04%, constraint element P≤0.015%, S≤0.012%, N≤0.006%, remaining is Fe and inevitable impurity.Production technology is：Smelting → continuous casting → hot rolling → cold rolling → galvanizing.Finishing elongation percentage 0.9~1.6%, straightening elongation percentage 0.2~0.4%.Advantage is, by controlling the component content of C, Si and Mn, the cold rolling low-alloy high-strength steel of combined process control production not only has excellent mechanical property, also reduces the segregation of ferritic-pearlitic type, and banded structure is rated 1.0 or less.

Description

Reduce the manufacture method of cold rolling low-alloy high-strength steel ferrite-pearlite type segregation
Technical field
The invention belongs to smelting iron and steel and Controlled Rolling And Controlled Cooling field, is specially a kind of reduction cold rolling low-alloy high-strength steel The manufacture method of ferritic-pearlite type segregation
Background technology
Cold rolling low-alloy high-strength steel is a kind of high-strength steel for automobile structure research and development, is added on a small quantity in mild steel Niobium and (or) the alloying element such as titanium, it is formed carbide, nitride with elements such as carbon, nitrogen and separated out on ferrite matrix So as to improve the intensity of steel, this steel has higher intensity and good forming property, is mainly used for automotive seat, crossbeam etc. Structural member and reinforcer.But when production tensile strength is more than 450Mpa intensity rank above low-alloy high-strength steels, often occur Ferrite-pearlite type is segregated, and segregation seriously shows as obvious banded structure, and usual banded structure is rated more than 2.0, this The cold formability energy of steel plate is reduced, is easy to cause stamping cracking.
The content of the invention
The purpose of the present invention is being more than the cold rolling low-alloy steel high-strength steel of 450Mpa for tensile strength intensity, exploitation is a kind of The manufacture method that low-alloy high-strength steel bends the segregation of ferrite-pearlite type is reduced, by rationally controlling alloy composition, optimization Hot rolling, cold-rolling process critical process system, eliminate the segregation of ferrite-pearlite type, solve in such steel grade punching course The problem of reducing forming property because being segregated and existing.
The present invention is taken the technical solution to be to reach above-mentioned purpose：
Institute the production procedure that uses for：Smelting → continuous casting → hot rolling → cold rolling → galvanizing.
Smelting and continuous casting：Determine the component of steel plate and mass percentage content is 0.045~0.075%C, 0.85~ 1.1%Mn, 0.15~0.25%Si, 0.025~0.055%Alt, 0.03~0.04%Nb, constraint element P≤0.015%, S ≤ 0.012%, N≤0.006%, remaining is Fe and inevitable impurity.
Hot rolling technology：Slab is heated to 1200~1280 DEG C from room temperature, when insulation 2.5~4 is small, afterwards by roughing and Finish to gauge, roughing outlet temperature are 1000~1200 DEG C, 850~910 DEG C of finishing temperature, 560~660 DEG C of coiling temperature.
Cold rolling：Hot rolled plate is 65~85% by carrying out cold rolling, cold rolling reduction ratio after hot rolling.
Hot dip galvanizing process is：740~800 DEG C of annealing soak temperature, belt speed use 80~120m/min slow cooling temperature as 650 ~720 DEG C, 430~480 DEG C of rapid cooling outlet temperature, finishing elongation percentage 0.9~1.6%, straightening elongation percentage 0.2~0.4%.
It is characteristic of the invention that：Micro Si is added in the cold rolling low-alloy high-strength steel of original C-Mn-Nb component systems, and C and Mn constituent contents are reduced, by optimizing finishing temperature in production process, coiling temperature, hot dip galvanizing annealing process system and control Belt speed processed, it is final to have excellent comprehensive mechanical property, and ferrite-pearlite is segregated low product, final cold rolling product Banded structure is controlled 1.0 or less.
The principle of the present invention：
1) selection principle of chemical composition
Steel grade should be noted that the element (Si, P, W, Mo, B etc.) of rise A3 and reduce element (Mn, Ni, Cr of A3 when designing Deng) between rational Design on Plane.In this way, alloying element is in interdendritic segregation, since the influence of several alloying elements is mutually supported Disappear, the A3 temperature difference between dendrite and limb is smaller, is conducive to that ferrite-pearlite segregation is mitigated or eliminated.
1)C:Carbon influences the intensity and forming property of steel band, welding performance very big, prompts to improve intensity most Economic primary colors, carbon content is high, and the elongation percentage of steel reduces, while be easy to cause segregation, present invention determine that carbon content be 0.045 ~0.075；
2) Si elements：Element silicon is deoxidant element, has certain solution strengthening effect, can improve A3, but can not be excessive, It has considerable influence to surface, consider present invention determine that element silicon content be 0.15~0.25%；
3) Mn elements：Manganese primary colors can reduce temperature of the austenite to ferritic transformation as solution strengthening element, excessive Manganese element the banded structure of steel plate can be caused obvious, increase and consider, the scope of manganese element of the invention is 0.85-1.0%.
2) operation principle of production method of the present invention：
Hot rolling technology：Reduce finishing temperature and be close to temperature Ar3 of the austenite to ferritic transformation, finish to gauge temperature of the present invention Degree uses 850~910 DEG C, using the ultrafast cold formation for suppressing pro-eutectoid ferritic quickly through two-phase section, and improves and batches temperature Degree makes it improve uniform change amount of the pearlite in hot rolling technology close to A1 lines；Coiling temperature of the present invention uses 560~660 DEG C；
Cold-rolling process：Segregation situation substantially deteriorates after the production of zinc-plated process, after banded structure rank is than hot-rolled process Higher, occur the reason for this phenomenon roll production mainly due to acid after cause secondary banding to be formed in zinc-plated production process, acid rolls Strip is set to form higher distortion in the case of drafts is larger, pearlite is easier to carry out transformation formation partially along Zona transformans Poly-, cold rolling reduction ratio of the present invention uses 65~85%；
Continuously dip coat zinc technology：In coexistence region part pearlite back dissolving in the case that annealing temperature is higher, work as cooling velocity The banded structure body of pro-eutectoid ferrite and pearlite interleaved and the band of pearlite interleaved are more easily produced when slower Shape tissue.740~800 DEG C of annealing soak temperature, belt speed use 80~120m/min, and slow cooling temperature is 650~720 DEG C, rapid cooling 430~480 DEG C of outlet temperature, finishing elongation percentage 0.9~1.6%, straightening elongation percentage 0.2~0.4%.
Brief description of the drawings
Fig. 1 be case study on implementation of the present invention in sample sequence number 1 acquisition metallographic structure photo figure, can be clearly seen ferrite- Pearlite segregation is less.
Fig. 2 be case study on implementation of the present invention in sample sequence number 2 acquisition metallographic structure photo figure, can be clearly seen ferrite- Pearlite segregation is less.
Fig. 3 be case study on implementation of the present invention in sample sequence number 3 acquisition metallographic structure photo figure, can be clearly seen ferrite- Pearlite segregation is less.
Fig. 4 be case study on implementation of the present invention in sample sequence number 4 acquisition metallographic structure photo figure, can be clearly seen ferrite- Pearlite segregation is less.
Fig. 5 be case study on implementation of the present invention in sample sequence number 5 acquisition metallographic structure photo figure, can be clearly seen ferrite- Pearlite segregation is less.
Embodiment
The present invention have studied mechanics of the cold rolling low-alloy high-strength steel of different chemical composition under the conditions of various processes Performance characteristics, chemical composition are shown in Table 1.
Table 1：Chemical composition surplus Fe
Sequence number C Si Mn P S Alt Nb N
1 0.06 0.18 0.86 0.009 0.004 0.041 0.03 0.002
2 0.06 0.24 0.97 0.008 0.007 0.055 0.03 0.004
3 0.07 0.2 1.01 0.011 0.011 0.04 0.04 0.0035
4 0.05 0.2 0.85 0.007 0.004 0.04 0.04 0.002
5 0.06 0.25 0.94 0.009 0.007 0.05 0.035 0.004
Corresponding hot rolling and cold-rolling production process are shown in Table 2.
Table 2：Hot rolling and cold-rolling production process
Sequence number Finishing temperature, DEG C Coiling temperature, DEG C Cold rolling reduction ratio, %
1 890 600 71
2 870 580 68
3 900 570 82
4 880 640 73
5 910 620 79
Corresponding hot dip galvanizing production process is shown in Table 3.
Table 3：Hot dip galvanizing production process
Corresponding final finished mechanical property is shown in Table 4.
Table 4：Finished product mechanical property
Sequence number Rp0.2/Mpa Rm/Mpa A80/% Banded structure is graded
1 414 479 26.5 0.5
2 424 498 26.5 1.0
3 453 531 22.5 0.5
4 389 493 21.5 0.5
5 446 526 21.5 1.0
As it can be seen that according to requirement of the present invention, the cold rolling low-alloy high-strength steel produced has excellent synthesis mechanics Performance, eliminates ferrite-pearlite segregation, and banded structure is rated 1.0 or less.

Claims (1)

  1. A kind of 1. manufacture method for reducing the segregation of cold rolling low-alloy high-strength steel ferrite-pearlite type, it is characterised in that：
    Steel billet is smelted, controls the chemical composition of smelting, the mass percentage of steel plate each element is：C:0.045~0.075%, Mn:0.85~1.1%Mn, Si:0.15~0.25%, Alt:0.025~0.055%, Nb:0.03~0.04%, constraint element P ≤ 0.015%, S≤0.012%, N≤0.006%, remaining is Fe and inevitable impurity；Then steel billet is connected successively Casting, hot rolling, cold rolling, hot dip galvanizing process, it is final to obtain the cold rolling low-alloy high-strength steel for seeing that tensile strength is more than 450Mpa；
    Hot rolling：Control heating-up temperature be 1200~1280 DEG C, insulation 2.5~4 it is small when after, roughing outlet temperature be 1000~1200 DEG C, finishing temperature is 850~910 DEG C, and coiling temperature is 560~660 DEG C；
    Cold rolling：It is 65~85% to control cold rolling reduction ratio；
    Galvanizing；740~800 DEG C of annealing soak temperature is controlled, belt speed uses 80~120m/min, and it is 650 to control slow cooling temperature ~720 DEG C, 430~480 DEG C of control rapid cooling outlet temperature, finishing elongation percentage 0.9~1.6%, straightening elongation percentage 0.2~0.4%.
CN201710949347.4A 2017-10-12 2017-10-12 Reduce the manufacture method of cold rolling low-alloy high-strength steel ferritic-pearlitic type segregation Pending CN107904478A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113528931A (en) * 2021-05-26 2021-10-22 唐山钢铁集团高强汽车板有限公司 Steel strip and production method thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106893933A (en) * 2017-04-06 2017-06-27 首钢总公司 A kind of production method of Hi-Stren steel
CN107083520A (en) * 2017-03-10 2017-08-22 唐山钢铁集团有限责任公司 A kind of low-alloy high-strength steel plate and its production method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107083520A (en) * 2017-03-10 2017-08-22 唐山钢铁集团有限责任公司 A kind of low-alloy high-strength steel plate and its production method
CN106893933A (en) * 2017-04-06 2017-06-27 首钢总公司 A kind of production method of Hi-Stren steel

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113528931A (en) * 2021-05-26 2021-10-22 唐山钢铁集团高强汽车板有限公司 Steel strip and production method thereof

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