• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2022, Vol. 58 ›› Issue (16): 43-50.doi: 10.3901/JME.2022.16.043

• 特邀专栏: 高性能塑性成形制造(上) • 上一篇    下一篇

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超高强度钢的短流程热成形工艺及其微观组织演化

侯泽然1, 王建锋2, 卢琦2, 闵峻英1, 何志康1, 张显1, 汪锦成1, 林建平1   

  1. 1. 同济大学机械与能源工程学院 上海 201804;
    2. 通用汽车中国科学研究院 上海 201206
  • 收稿日期:2021-11-29 修回日期:2022-04-03 出版日期:2022-08-20 发布日期:2022-11-03
  • 通讯作者: 闵峻英(通信作者),男,1986年出生,博士,教授,博士研究生导师。主要研究方向为汽车轻量化与先进成形制造技术。E-mail:junying.min@tongji.edu.cn
  • 作者简介:侯泽然,男,1989年出生,博士后。主要研究方向为高强韧汽车钢。E-mail:zeranhou@tongji.edu.cn
  • 基金资助:
    国家自然科学基金资助项目(52105395)

Short Process Hot Forming Technology and Microstructure Evolution of Ultra-high Strength Steels

HOU Zeran1, WANG Jianfeng2, LU Qi2, MIN Junying1, HE Zhikang1, ZHANG Xian1, WANG Jincheng1, LIN Jianping1   

  1. 1. School of Mechanical Engineering, Tongji University, Shanghai 201804;
    2. China Science Lab, General Motors Global Research & Development, Shanghai 201206
  • Received:2021-11-29 Revised:2022-04-03 Online:2022-08-20 Published:2022-11-03

摘要: 在降碳和安全的大背景下,汽车用超高强度钢的发展面临新的挑战。通过改变冷轧板的退火工艺,将退火组织转化为马氏体,可大幅提高热成形过程中材料完全奥氏体化的效率,从而缩短热成形所需的总加热时间。基于此,将新材料和新工艺相结合,提出了短流程热成形工艺。以免镀层热成形钢为例,研究了短流程热成形工艺下钢的微观组织演化及力学性能。结果表明,初始组织为马氏体和碳化物的免镀层钢,以100 ℃/s加热至930 ℃,保温30 s以内可实现完全奥氏体化,并获得马氏体和3%~5%残余奥氏体的混合组织,且最终材料具备较高的强韧性,其抗拉强度可达1 578 MPa,伸长率为7.8%。由此,热成形所需的总加热时间可缩短至1 min以内,相比传统硼钢板热成形工艺所需的5 min加热时间,短流程热成形新工艺在保证零件强韧性的同时将总加热时间缩短了80%以上,可有效助力节能降碳。

关键词: 热成形钢, 短流程, 马氏体, 快速加热

Abstract: Under the background of carbon reduction and safety, the development of ultra-high strength steels for automobiles are facing new challenges. By changing the annealing process of the cold-rolled sheet, the annealed microstructure could be transformed into martensite. The efficiency of complete austenitization of the material in the hot forming process can be greatly improved, thereby shortening the total heating time required for hot forming. A short-flow hot forming process was proposed by combining new materials and new processes. Taking coating-free hot forming steel as an example, the microstructure evolution and mechanical properties of steel under short-flow hot forming process are studied. Results shown that the non-plating steel with the initial structure of martensite and carbide can be fully austenitized by heating at 100 ℃/s to 930 ℃ and holding for 30 s, and martensite and 3%-5% retained austenite can be obtained. The final material owns high strength and toughness: with tensile strength of 1 578 MPa, and elongation of 7.8%. Therefore, the heating time required for hot forming can be shortened to less than 1 min. Compared with the 5 min heating time required for traditional hot forming process of boron steel plate, the short process hot forming technology reduces the total heating time by more than 80% while ensuring the strength and toughness of the parts, which can effectively help energy saving and carbon reduction.

Key words: hot forming steel, short process, martensite, rapid heating

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