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  • ISSN：0577-6686
机械工程学报

机械工程学报 ›› 2017, Vol. 53 ›› Issue (12): 110-117.doi: 10.3901/JME.2017.12.110

• 第三代高强钢汽车板 • 上一篇    下一篇

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汽车用超高强QP钢的工艺与组织性能研究

朱国明1, 康永林1,2, 朱帅1   

  1. 1. 北京科技大学材料科学与工程学院 北京 100083；
    2. 北京科技大学材料先进制备技术教育部重点实验室 北京 100083
  • 出版日期:2017-06-20 发布日期:2017-06-20
  • 作者简介:

    朱国明，男，1974年出生，博士，副教授。主要研究方向为金属塑性成形工艺与数值模拟。

    E-mail：zhuguoming@ustb.edu.cn

    康永林(通信作者)，男，1954年出生，博士，教授，博士研究生导师。主要研究方向为新一代汽车用钢的开发及应用。

    E-mail：kangylin@ustb.edu.cn

  • 基金资助:
    * 国家自然科学基金资助项目(U1460101); 20160627收到初稿，20161121收到修改稿;

Study on Process， Microstructure and Property of Ultra-high Strength QP Steel for Automobile

ZHU Guoming1, KANG Yonglin1,2, ZHU Shuai1   

  1. 1. School of Materials Science and Engineering， University of Science and Technology Beijing， Beijing 100083;
    2. Key Laboratory for Advanced Materials Processing of Ministry of Education， University of Science and Technology Beijing， Beijing 100083
  • Online:2017-06-20 Published:2017-06-20

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摘要：

介绍以简单成分C-Si-Mn及其Nb，Ti微合金化为特点的第三代汽车用钢淬火配分(Quenching & partioning， QP)钢的研究结果，包括：不同配分温度和配分时间等配分条件对QP钢组织性能的影响，淬火和在贝氏体区配分QP-B条件对QP钢组织性能的影响，以及配分条件对QP钢的加工硬化行为和烘烤硬化性能的影响规律等。结果表明，微合金化可有效减小原始奥氏体晶粒尺寸;采用淬火并在贝氏体区配分(Quenching and partitioning in bainite zone，QP-B)的热处理工艺可得到M+B+γ三相组织及7.81%的较高奥氏体体积分数，强塑积可达到31.6 GPa?%;QP钢具有的优异加工硬化性能与组织中的残余奥氏体含量密切相关，残余奥氏体含量可以通过优化配分工艺调整;简单成分QP钢(0.24C-1.5Si-2.1Mn-0.05Nb)的烘烤硬化值随配分温度及配分时间的增加从80 MPa降低到30 MPa左右。

关键词: 残余奥氏体, 淬火, 配分, 组织性能, 汽车用钢

Abstract:

The third generation automotive quenching & portioning(QP) steel is introduced, which adopted a simple C-Si-Mn alloy system and Nb, Ti micro-alloying. The influence of partitioning process, such as partitioning temperature and time, on microstructure, mechanical property, work hardening behavior and bake hardening property of QP steel are studied. The process of quenching and partitioning in bainite zone (QP-B) is also investigated. The result shows that the prior austenite grain size decreased effectively via micro-alloyed. A triphase microstructure of martensite+bainite+austenite with a high austenite volume fraction of 7.81% is obtained by the QP-B process, the product of strength and ductility reached 31.6 GPa·%. The excellent work hardening property of Q&P steel is related to the volume fraction of retained austenite, which can be controlled by optimizing the partitioning process. The bake hardening value of the studied Q&P steel (0.24C-1.5Si-2.1Mn-0.05Nb) decreased from 80 MPa to about 30 MPa with the increase of partitioning temperature and time.

Key words: microstructure-properties, partitioning, quenching, retained austenite, automobile steel

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