A method for manufacturing cold-rolled ultra-high-strength dual-phase steel with high partial formability

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: 2018-04-10
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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 is still the problem of steel plate oxidation after water cooling, which needs to cooperate with the subsequent pickling process, making production more difficult

Method used

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  • A method for manufacturing cold-rolled ultra-high-strength dual-phase steel with high partial formability

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] According to the percentage by weight: C 0.1%, Si 0.2%, Mn 2.0%, Al 0.04%, the rest is Fe and the chemical composition of inevitable impurity elements to select raw materials and melt them into billets; heat the billets at 1200°C for 2 hours Afterwards, hot rolling is carried out, the starting rolling temperature is 1150°C, the final rolling temperature is 890°C, and after rolling, it is cooled to 500°C at a cooling rate of 50°C / s for coiling to obtain a hot-rolled steel plate with bainite as the main structure type; The hot-rolled steel plate is pickled and then cold-rolled. The reduction rate of cold rolling is 80%. Then it is heated to 740°C at a heating rate of 250°C / s for annealing. Cool to 680°C, and then cool to 300°C at a cooling rate of 40°C / s for 5 minutes of overaging 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....

Embodiment 2

[0042] According to the percentage by weight: C 0.11%, Si 0.4%, Mn 1.9%, Al 0.03%, the rest is Fe and the chemical composition of inevitable impurity elements, the raw materials are selected and smelted into slabs; the slab is heated at 1200°C for 2 hours Afterwards, hot rolling is carried out, the starting rolling temperature is 1120°C, the final rolling temperature is 880°C, and after rolling, it is cooled to 450°C at a cooling rate of 150°C / s for coiling to obtain a hot-rolled steel plate with bainite as the main structure type; The hot-rolled steel plate is pickled and then cold-rolled. The reduction rate of cold rolling is 50%. Then it is heated to 750°C at a heating rate of 100°C / s for annealing. Cool to 650°C, and then cool 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 the yield strength R p0.2 =665MPa, tensile strength R m =1047MPa, elongation A 5...

Embodiment 3

[0044] According to the percentage by weight: C 0.09%, Si 0.1%, Mn 1.5%, Al 0.04%, the rest is Fe and the chemical composition of inevitable impurity elements to select raw materials and melt them into slabs; heat the slab at 1200°C for 2 hours Afterwards, hot rolling is carried out, the starting rolling temperature is 1130°C, the final rolling temperature is 900°C, and after rolling, it is cooled to 550°C at a cooling rate of 80°C / s for coiling to obtain a hot-rolled steel plate with bainite as the main structure type; The hot-rolled steel plate was pickled and then cold-rolled. The cold-rolling reduction rate was 60%, and then heated to 780°C at a heating rate of 300°C / s for annealing, and kept for 30s and then slowly cooled at a cooling rate of 3°C / s. Cool to 650°C, 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...

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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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Patent Type & Authority Patents(China)
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 LIAONING
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