金属热处理 ›› 2024, Vol. 49 ›› Issue (2): 32-39.DOI: 10.13251/j.issn.0254-6051.2024.02.005

• 组织与性能 • 上一篇    下一篇

超快冷工艺制备的超高强度马氏体钢的显微组织和性能

刘自权1, 栗克建2, 张龙柱1, 李守华1, 冯毅3, 曹鹏军2   

  1. 1.河钢集团邯钢公司 技术中心, 河北 邯郸 056015;
    2.重庆科技大学 冶金与材料工程学院, 重庆 401331;
    3.中国汽车工程研究院股份有限公司, 重庆 401122
  • 收稿日期:2023-09-06 修回日期:2024-01-06 出版日期:2024-03-27 发布日期:2024-03-27
  • 通讯作者: 栗克建,高级工程师,博士,E-mail:likejiann@cqust.edu.cn
  • 作者简介:刘自权(1989—),男,高级工程师,硕士,主要研究方向为汽车用钢产品研发,E-mail:liuziquan@hbisco.com。
  • 基金资助:
    河北省重大科技成果转化专项(18041033Z)

Microstructure and properties of ultra-high strength martensitic steel prepared by ultra-fast cooling process

Liu Ziquan1, Li Kejian2, Zhang Longzhu1, Li Shouhua1, Feng Yi3, Cao Pengjun2   

  1. 1. Technology Centre, HBIS Hansteel, Handan Hebei 056015, China;
    2. School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331, China;
    3. China Academy of Automotive Engineering Co., Ltd., Chongqing 401122, China
  • Received:2023-09-06 Revised:2024-01-06 Online:2024-03-27 Published:2024-03-27

摘要: 利用超快冷工艺制备不同Mn添加量(1.01%、1.41%和1.74%,质量分数)的超高强度马氏体钢,采用XRD、SEM、EBSD、TEM等技术手段对比分析试验钢的原始奥氏体晶粒尺寸、高角度晶界比例、马氏体板条厚度和纳米析出相等显微组织差异,利用TDA技术分析了钢的抗氢脆性能,同时利用第一性原理研究钢中Cu析出相界面处的氢陷阱。结果表明,随着Mn添加量的增加,1500 MPa级马氏体钢的原始奥氏体晶粒尺寸均约为7 μm,但高Mn试样的马氏体板条更细、更密。第一性原理计算证明Cu与马氏体钢基体界面处可以形成良性氢陷阱,马氏体组织中大量的各类界面有助于在钢中形成更加分散的氢陷阱,氢在材料中就不容易局部聚集,从而降低材料氢脆断裂风险。基于超快冷工艺,Mn添加量增加可以实现1500 MPa级马氏体钢获得更多界面组织,微量的Cu析出也可以进一步提升材料的抗氢脆性能。

关键词: 马氏体钢, 氢脆, 残留奥氏体, 氢陷阱, 第一性原理

Abstract: Ultra-high strength martensitic steel with different Mn additions (1.01%, 1.41% and 1.74%, mass fraction) was prepared by ultra-fast cooling process, and the differences of microstructure, such as the prior austenite grain size, high-angle grain boundary ratio, thickness of martensite lath and nanoprecipitates were compared by XRD, SEM, EBSD and TEM. The hydrogen embrittlement property of the steel was analysed by TDA. The first-principles were used to study the hydrogen trap at the interface of the Cu precipitates and steel matrix. The results show that with the increase of Mn addition, the prior austenitic grain size of 1500 MPa grade martensitic steel is about 7 μm, but the martensitic lath in higher Mn specimen is thinner and denser. First-principles calculations show that harmless hydrogen traps can be formed at the interface between Cu and martensitic steel matrix, and a large number of various interfaces in the martensitic structure help to form more dispersed hydrogen traps in the steel, so that hydrogen is not easy to accumulate locally in the material, thereby reducing the risk of hydrogen embrittlement of the material. Based on the ultra-fast cooling process, the increase of Mn addition can achieve finer microstructure of 1500 MPa grade martensitic steel, and the Cu precipitation can also improve the hydrogen embrittlement resistance of the steel.

Key words: martensitic steel, hydrogen embrittlement, retained austenite, hydrogen trap, first principles

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