Aluminum-containing cold rolling ultrahigh strength steel as well as preparation method and application thereof

An ultra-high-strength steel and overaging technology, which is applied in the field of short-term overaging heat treatment for the preparation of aluminum-containing cold-rolled ultra-high-strength steel, can solve the problems of long heat treatment process and unfavorable large-scale production, so as to improve product competitiveness and alloy cost. The effect of economy, good strength and plastic ratio

Active Publication Date: 2020-10-02
MAANSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Aiming at the problem that the long heat treatment process of existing cold-rolled steel is not conducive to large-scale production, the present invention is based on the low-silicon and low-aluminum composition design, which is beneficial to the short-term overaging treatment method, and controls the matrix structure to be polygonal ferrite and bainite And the Maho island composed of twinned martensite and retained austenite, thus realizing the preparation of aluminum-containing cold-rolled ultra-high-strength steel

Method used

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  • Aluminum-containing cold rolling ultrahigh strength steel as well as preparation method and application thereof
  • Aluminum-containing cold rolling ultrahigh strength steel as well as preparation method and application thereof
  • Aluminum-containing cold rolling ultrahigh strength steel as well as preparation method and application thereof

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Experimental program
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Effect test

Embodiment 1

[0046] The aluminum-containing cold-rolled ultra-high-strength steel of this embodiment has the following chemical composition in terms of mass percentage: C: 0.20, Mn: 2.0, Si: 1.24, Al: 0.46, Nb: 0.029, Ti: 0.058, P: ≤ 0.007, N: ≤0.006, O: ≤0.003, S: ≤0.005, and the rest are Fe and other unavoidable impurities.

[0047] Smelting based on the above ingredients to obtain a slab with a thickness of 100mm, and hot rolling according to the following process: heat the slab to 1200°C and keep it warm for 4 hours, and then roll it 7 times to obtain a hot-rolled plate with a thickness of 4.5mm , the starting rolling temperature is 1125°C, and the finishing rolling temperature is 875°C. The hot rolling adopts a 4-high reversing rolling mill for 7 passes of reciprocating rolling. The reduction rates are 20-30% respectively, that is, the reduction rates of the first two passes each time must be higher than those of the last five passes. After hot-rolling, water-cool to 650°C and put in...

Embodiment 2

[0050] The aluminum-containing cold-rolled ultra-high-strength steel of this embodiment has the following chemical composition in terms of mass percentage: C: 0.18, Mn: 1.5, Si: 1.0, Al: 0.3, Nb: 0.02, Ti: 0.2, P: ≤ 0.015, N: ≤0.006, O: ≤0.003, S: ≤0.005, and the rest are Fe and other unavoidable impurities.

[0051] Smelting based on the above components to obtain a slab with a thickness of 100mm, and hot rolling according to the following process: heating the slab to 1100°C and holding it for 3 hours, and rolling it 7 times to obtain a hot-rolled plate with a thickness of 4mm. The starting rolling temperature is 1050°C, and the final rolling temperature is 850°C. The hot rolling adopts a 4-high reversing rolling mill for 7 passes of reciprocating rolling. The reduction rates are 20-30%, that is, the reduction rates of the first two passes each time must be higher than those of the last five passes. After hot-rolling, air-cool to 650°C and put in asbestos for 8 hours, then c...

Embodiment 3

[0054] The aluminum-containing cold-rolled ultra-high-strength steel of this embodiment has the following chemical composition in terms of mass percentage: C: 0.22, Mn: 2.5, Si: 1.5, Al: 0.8, Nb: 0.04, Ti: 0.6, P: ≤ 0.015, N: ≤0.006, O: ≤0.003, S: ≤0.005, and the rest are Fe and other unavoidable impurities.

[0055] Smelting based on the above components to obtain a slab with a thickness of 100mm, and hot rolling according to the following process: heating the slab to 1200°C and holding it for 5 hours, and rolling it 7 times to obtain a hot-rolled plate with a thickness of 4mm. The starting rolling temperature is 1150°C, the final rolling temperature is 900°C, and the hot rolling adopts a 4-high reversing rolling mill for 7 passes of reciprocating rolling. The reduction rates are 20-30%, that is, the reduction rates of the first two passes each time must be higher than those of the last five passes. After hot-rolling, air-cool to 750°C and put in asbestos for 10 hours, then ...

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Abstract

The invention discloses aluminum-containing cold rolling ultrahigh strength steel as well as a preparation method and application thereof and belongs to the technical field of material thermal treatment. The cold rolling ultrahigh strength steel is composed of polygonal ferrite, bainite and martensite/austenite islands; the martensite/austenite islands are composed of twin crystal martensite and retained austenite; the cold rolling ultrahigh strength steel is obtained through short overaging treatment; the time of short overaging treatment is 20-80 s, and the temperature of short overaging treatment is 400 DEG C; the preparation method comprises the following steps: smelting, forging, hot rolling, cold rolling, and thermal treatment; and during the thermal treatment process, two-phase region annealing is adopted to raise the temperature to 790-830 DEG C at the heating rate of 10-30 DEG C/s, thermal insulation is carried out for 3-8 minutes, the temperature is cooled to 400 DEG C at therate of 80-150 DEG C/s, then, short overaging treatment is carried out for 20-80 s, and the temperature is cooled to the room temperature. With adoption of the preparation method, high-strength and high-plasticity automobile steel is prepared through short overaging treatment, so that production energy consumption is greatly reduced, the cost is decreased, and the product competitiveness is improved.

Description

technical field [0001] The invention belongs to the technical field of heat treatment of materials, and more specifically relates to the field of advanced high-strength steel for third-generation automobiles, in particular to a short-time overaging heat treatment method for preparing aluminum-containing cold-rolled ultra-high-strength steel. Background technique [0002] Since the 21st century, the rapid development of the automobile industry has brought convenience, but it has also caused serious practical problems such as environmental pollution and energy consumption. received people's attention. In the composition design of automobile steel, in order to inhibit the precipitation of cementite and realize the carbon-rich stability of austenite, a certain amount of silicon element is generally added, generally 1.5-2.0% (mass fraction). However, the increase of silicon content will deteriorate the surface quality of the product, which is not conducive to the subsequent galv...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/04C22C38/02C22C38/06C22C38/12C22C38/14C21D8/02C21D1/26
CPCC21D1/26C21D8/0226C21D8/0236C21D8/0247C21D2211/001C21D2211/002C21D2211/005C21D2211/008C22C38/02C22C38/04C22C38/06C22C38/12C22C38/14
Inventor 詹华肖洋洋冷德平崔磊刘永刚晋家春
Owner MAANSHAN IRON & STEEL CO LTD
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