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Cold-rolled dual-phase steel DP780 and flexible production method thereof

A production method and dual-phase steel technology, which is applied in the field of cold-rolled dual-phase steel preparation, can solve problems such as cracking, and achieve the effects of good material fluidity, improved baking performance, and strong uniform deformation ability

Active Publication Date: 2019-07-16
BENGANG STEEL PLATES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The above technical solutions all consider the cost of the enterprise, and use one composition system to realize the preparation of high-strength steel with different strength requirements, while the cold-rolled dual-phase steel DP780 is used in the production of automobile B-pillars, seat frames and other components with more complex shapes by stamping. , especially in local forming processes such as small-radius bending and stretching flanges, cracking often occurs, so automobile factories have an urgent demand for materials with high formability
At the same time, due to the design requirements of different models and parts, automobile factories have different requirements for the performance indicators of cold-rolled dual-phase steel DP780, such as yield strength requirements, elongation requirements, n value, r value and BH2 value requirements, the above technical solutions The demand for high formability of the automobile factory is not considered. Based on the above situation, it is necessary to prepare a cold-rolled cold-rolled steel sheet with uniform microstructure and good formability, which can meet the individual needs of the automobile factory, and is beneficial to cost reduction and efficiency increase for steel production enterprises. Duplex steel DP780

Method used

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  • Cold-rolled dual-phase steel DP780 and flexible production method thereof
  • Cold-rolled dual-phase steel DP780 and flexible production method thereof
  • Cold-rolled dual-phase steel DP780 and flexible production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] A cold-rolled dual-phase steel DP780, the production process is: molten steel pretreatment→converter smelting→external refining→continuous casting→hot rolling heating→rough rolling, finishing rolling→controlled cooling→coiling→cold rolling decoiling, Weldingpickling, cold rolling→continuous annealing→leveling→surface and performance inspection→packing→delivery; the composition of cold-rolled dual-phase steel DP780 is calculated by weight percentage: C: 0.15, Si: 0.20, Mn: 1.1, Ti: 0.02 , Cr: 0.10~0.20, Al: 0.04, P: ≤0.015, S: ≤0.010, and the rest are Fe and unavoidable impurities, that is, through the steelmaking-hot rolling-cold rolling-annealing preparation process, using one component to produce Process control, yield strength 400 ~ 650MPa, tensile ≥ 780MPa, elongation A 80 ≥18%, n 10-20 / Ag value ≥ 0.14, r 90 Value ≥ 0.8, BH 2 ≥50MPa performance index. Hot rolling process design: final rolling temperature: 850°C; coiling temperature: 550°C. Cold rolling, anneal...

Embodiment 2

[0046] Manufacture of seat reinforcements by press forming

[0047] The production process of cold-rolled dual-phase steel DP780 is: pretreatment of molten steel → converter smelting → refining outside the furnace → continuous casting → hot rolling heating → rough rolling, finishing rolling → controlled cooling → coiling → cold rolling uncoiling, welding → acid Washing, cold rolling→continuous annealing→leveling→surface, performance inspection, composition by weight percentage, including C: 0.13, Si: 0.10, Mn: 1.0, Ti: 0.01, Cr: 0.10, Al: 0.02, P: ≤0.015 , S: ≤0.010, the rest are Fe and unavoidable impurities. Through the steelmaking-hot rolling-cold rolling-annealing preparation process, one component is used to control the production process, and the martensite volume fraction of cold-rolled dual-phase steel DP780 is about 16%, the average grain size is 3μm, and the yield strength 425MPa, tensile strength ≥ 815MPa, elongation A 80 ≥22.5%, n 10-20 / Ag value ≥ 0.16, r 90 Va...

Embodiment 3

[0049] The production process of cold-rolled dual-phase steel DP780 is: pretreatment of molten steel → converter smelting → refining outside the furnace → continuous casting → hot rolling heating → rough rolling, finishing rolling → controlled cooling → coiling → cold rolling uncoiling, welding → acid Washing, cold rolling→continuous annealing→leveling→surface, performance inspection, composition by weight percentage, including C: 0.13, Si: 0.10, Mn: 1.0, Ti: 0.01, Cr: 0.10, Al: 0.02, P: ≤0.015 , S: ≤0.010, the rest is Fe and unavoidable impurities; the martensite volume fraction of the cold-rolled dual-phase steel DP780 in this example is about 19%, the average grain size is 4μm, the yield strength is 613MPa, and the tensile strength is ≥835MPa , elongation A 80 ≥22%, n 10-20 / Ag value ≥ 0.16, r 90 Value ≥ 0.9, BH 2 ≥63. After punchingwelding→longitudinal roll formingspot welding→bending forming→shearing→cutting to length, the finished parts are finally made into finishe...

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Abstract

The invention belongs to the technical field of preparation of cold-rolled dual-phase steel, and relates to cold-rolled dual-phase steel DP780 and a flexible production method thereof. The cold-rolleddual-phase steel DP780 comprises the components according to the percentage by weight: 0.13 to 0.17 of C, 0.10 to 0.40 of Si, 1.0 to 1.2 of Mn, 0.01 to 0.04 of Ti, 0.10-0.20 of Cr, 0.02-0.06 of Al, less than or equal to 0.015 of P, less than or equal 0.010 of S, and the balance being Fe and inevitable impurities. The cold-rolled dual-phase steel DP780 prepared by the method has uniform tissue distribution, martensite volume fraction of less than 20%, average grain size of 3-4 micrometers, yield strength of 400-650 MPa, tensile strength of greater than or equal to 780 MPa, elongation percentage A80 of greater than or equal to 18%, n10-20 / Ag value of greater than or equal to 0.14, r90 value of greater than or equal to 0.8, and BH2 of greater than or equal to 50 MPa and can meet the requirements of automobile factories on individualization and high forming property.

Description

technical field [0001] The invention belongs to the technical field of cold-rolled dual-phase steel preparation, and relates to a cold-rolled dual-phase steel DP780 and a flexible production method thereof. Background technique [0002] The lightweight of automobile bodies has become an effective method to reduce exhaust emissions and fuel consumption. Due to its low yield ratio, high initial work hardening rate and good strength and toughness, dual-phase steel has become the most widely used advanced steel in automobile body manufacturing. High-strength steel, according to the individual needs of automobile factories, through the process control of the production process, a cold-rolled dual-phase steel suitable for different standards is developed. [0003] The commonly used preparation method of the cold-rolled dual-phase steel, the prior art is as follows: Document 1: It mainly refers to the realization of the use of a single composition through reasonable, economical, lo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/28C22C38/06C21D8/02
CPCC21D8/0226C21D8/0236C21D8/0247C21D2211/005C21D2211/008C22C38/02C22C38/04C22C38/06C22C38/28
Inventor 王亚东刘宏亮李春诚董雪涛王亚芬卢秉仲
Owner BENGANG STEEL PLATES
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