Method for manufacturing cold-rolled ultrahigh-strength dual-phase steel with high local forming performance

A technology of formability and manufacturing method, which is applied in the field of metallurgy, can solve problems such as difficulty in ensuring plate shape, increased production difficulty, and large steel plate stress, and achieve the effects of solving poor plasticity and formability, reducing component costs, and low cost

Active Publication Date: 2016-05-04
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the internal stress of the steel plate is large under high cooling rate, and the shape of the plate is difficult to guarantee; in addition, there ...

Method used

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  • Method for manufacturing cold-rolled ultrahigh-strength dual-phase steel with high local forming performance

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] According to the percentage by weight: C0.1%, Si0.2%, Mn2.0%, Al0.04%, the rest is the chemical composition of Fe and unavoidable impurity elements to select raw materials, smelt into cast slabs; cast slabs at 1200 After heating at ℃ for 2 hours, hot rolling is carried out. The starting rolling temperature is 1150 ℃, and the final rolling temperature is 890 ℃. Hot-rolled steel plate; cold-rolled the hot-rolled steel plate after pickling, the cold-rolled reduction rate is 80%, then heated to 740°C at a heating rate of 250°C / s for annealing, and kept at 5°C / s for 3 minutes Slowly cool to 680°C at a cooling rate of 40°C / s, and then cool to 300°C at a cooling rate of 40°C / s for 5 minutes to obtain an ultra-high-strength dual-phase steel with a ferrite + martensite dual-phase structure, and the yield strength R p0.2 =650MPa, tensile strength R m =1023MPa, elongation A 50mm =12.7%, 180o bending along the rolling direction without cracking.

Embodiment 2

[0042] According to the percentage by weight: C0.11%, Si0.4%, Mn1.9%, Al0.03%, the rest is the chemical composition of Fe and unavoidable impurity elements to select raw materials and melt them into cast slabs; After heating at ℃ for 2 hours, hot rolling is carried out. The starting rolling temperature is 1120 ℃, and the final rolling temperature is 880 ℃. Hot-rolled steel plate; cold-rolled the hot-rolled steel plate after pickling, the cold-rolled reduction rate is 50%, then heated to 750°C at a heating rate of 100°C / s for annealing, and kept at 5°C / s for 2 minutes slow cooling to 650°C at a cooling rate of 60°C / s, and then cooling to 330°C at a cooling rate of 60°C / s for 5 minutes of overaging to obtain an ultra-high-strength dual-phase steel with a ferrite + martensite dual-phase structure and a yield strength of R p0.2 =665MPa, tensile strength R m =1047MPa, elongation A 50mm =12.3%, 180o bending along the rolling direction without cracking.

Embodiment 3

[0044] According to the percentage by weight: C0.09%, Si0.1%, Mn1.5%, Al0.04%, the rest is the chemical composition of Fe and unavoidable impurity elements to select raw materials and melt them into cast slabs; After heating at ℃ for 2 hours, hot rolling is carried out. The starting rolling temperature is 1130 ℃, and the final rolling temperature is 900 ℃. After rolling, it is cooled to 550 ℃ at a cooling rate of 80 ℃ / s for coiling. Hot-rolled steel plate: cold-roll the hot-rolled steel plate after pickling, the cold-rolled reduction rate is 60%, and then heat it to 780°C at a heating rate of 300°C / s for annealing, and hold it for 30s and then heat it at 3°C / s Slowly cool to 650°C at a cooling rate of 30°C / s, then cool to 300°C at a cooling rate of 30°C / s and over-age for 5 minutes to obtain an ultra-high-strength dual-phase steel with a ferrite + martensite dual-phase structure, and the yield strength R p0.2 =575MPa, tensile strength R m =987MPa, elongation A 50mm =15.6%, 1...

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Abstract

The invention relates to a method for manufacturing cold-rolled ultrahigh-strength dual-phase steel with high local forming performance. The method comprises the process steps that 1, chemical components which comprise, by weight percent, 0.08%-0.12% of C, 0.1%-0.5% of Si, 1.5%-2.5% of Mn, 0.015%-0.05% of Al and the balance Fe and inevitable impurities are selected as raw materials, and the raw materials are smelted into a casting blank; 2, the casting blank is subjected to hot rolling after being heated at the temperature ranging from 1,150 DEG C to 1,250 DEG C for 1.5-2 hours, and after rolling, the casting blank is cooled to 450-620 DEG C at the cooling speed being 50-200 DEG C/s to be coiled; and 3, a hot-rolled steel plate is subjected to cold rolling, then the hot-rolled steel plate is heated to 740-820 DEG C at the speed of 50-300 DEG C/s for annealing, the hot-rolled steel plate is cooled to 620-680 DEG C at the cooling speed being 2-6 DEG C/s, then the hot-rolled steel plate is cooled to 250-350 DEG C at the cooling speed being 30-100 DEG C/s, and the ultrahigh-strength dual-phase steel is obtained.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for manufacturing cold-rolled ultra-high-strength dual-phase steel with high local formability. Background technique [0002] The weight of the car body can be reduced to reduce CO 2 emissions and reduce fuel consumption. However, due to the requirements for safety performance, the rigidity of the automobile body needs to be continuously improved. Strengthening the body structure and increasing the use of high-strength steel plates can improve its crash safety. Taking into account both cost and performance, high-strength steel plates are the best choice for lightweight car bodies and improved crash safety. In the European ultra-light steel car body design, the proportion of dual-phase steel exceeds 80%, of which the proportion of dual-phase steel above 800MPa exceeds 70%. [0003] However, as the strength of dual-phase steel increases, its formability ...

Claims

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Application Information

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IPC IPC(8): C22C38/04C22C38/02C22C38/06C21D8/02C21D6/00
CPCC21D6/005C21D8/0226C21D8/0236C21D8/0273C21D2211/005C21D2211/008C22C38/02C22C38/04C22C38/06
Inventor 蓝慧芳杜林秀李建平李强邱春林张俊潇王国栋
Owner NORTHEASTERN UNIV
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