金属热处理 ›› 2022, Vol. 47 ›› Issue (12): 13-18.DOI: 10.13251/j.issn.0254-6051.2022.12.003

• 工艺研究 • 上一篇    下一篇

淬火-长分配工艺对V-Ti-N微合金化高强钢组织和性能的影响

孙鼎博, 黄雪飞   

  1. 四川大学 材料科学与工程学院, 四川 成都 610065
  • 收稿日期:2022-07-29 修回日期:2022-10-26 出版日期:2022-12-25 发布日期:2023-01-05
  • 通讯作者: 黄雪飞,副教授,博士,E-mail:huangxf08@scu.edu.cn
  • 作者简介:孙鼎博(1997—),男,硕士研究生,主要研究方向为先进金属材料及制备加工,E-mail:sdb1838049232@163.com。
  • 基金资助:
    四川省重大科技专项(2020ZDZX0011)

Effect of quenching-long partitioning treatment on microstructure and mechanical properties of V-Ti-N microalloyed high strength steel

Sun Dingbo, Huang Xuefei   

  1. School of Materials Science and Engineering, Sichuan University, Chengdu Sichuan 610065, China
  • Received:2022-07-29 Revised:2022-10-26 Online:2022-12-25 Published:2023-01-05

摘要: 使用扫描电镜、X射线衍射仪、万能试验机和冲击试验机研究了淬火-长分配(Q-LP)工艺对V-Ti-N微合金化高强钢组织和性能的影响。结果表明,试验钢经一步Q-LP和两步Q-LP工艺处理后,其显微组织均由马氏体、残留奥氏体和少量贝氏体组成。随着分配时间的延长,各试样中残留奥氏体含量均减少,但在相同分配时间下,两步Q-LP试样中的残留奥氏体含量高于一步Q-LP试样。一步Q-LP试样的屈服强度随分配时间的延长而降低,而伸长率和冲击性能随分配时间的延长而增加,分配时间为60 min时获得最佳的综合力学性能。两步Q-LP试样的屈服强度、伸长率和冲击性能随分配时间的延长先增加而后趋于稳定,分配时间为30 min时获得最佳的综合力学性能。在同一分配时间下,经两步Q-LP工艺处理的试样展现出的综合力学性能优于经一步Q-LP工艺处理的试样。相较于一步Q-LP试样,两步Q-LP试样中更多的残留奥氏体,以及更高分配温度导致的组织软化和残余内应力的释放,是提高其性能的关键。

关键词: 淬火-长分配工艺, 高强钢, 显微组织, 力学性能

Abstract: Effect of quenching-long partitioning (Q-LP) treatment on microstructure and mechanical properties of V-Ti-N microalloyed steel was investigated by means of scanning electron microscope, X-ray diffractometer, universal electronic material testing machine and pendulum impact testing machine. The results show that the microstructure of the tested steel is composed of martensite, retained austenite and a little bainite after the one-step Q-LP and two-step Q-LP treatments. The content of retained austenite in all specimens reduces with the prolonging of partitioning time. However, retained austenite content is higher in the two-step Q-LP specimens than in the one-step Q-LP specimens under the same partitioning time. The yield strength of the one-step Q-LP specimens reduces with the prolonging of partitioning time, while elongation and impact property increase. The one-step Q-LP specimen exhibits the most remarkable mechanical properties with the partitioning time of 60 min. The yield strength, elongation and impact property of the two-step Q-LP specimens increase first and then become stable with the prolonging of partitioning time. The two-step Q-LP specimen exhibits the most remarkable mechanical properties with the partitioning time of 30 min. Specimens treated by the two-step Q-LP process exhibit better mechanical properties than those treated by the one-step Q-LP process under the same partitioning time. Compared with one-step Q-LP specimens, more retained austenite in two-step Q-LP specimens, as well as microstructure softening and residual stress release caused by higher partitioning temperature, are the key to improve the properties of the two-step Q-LP specimens.

Key words: quenching-long partitioning treatment, high strength steel, microstructure, mechanical properties

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