金属热处理 ›› 2023, Vol. 48 ›› Issue (10): 59-65.DOI: 10.13251/j.issn.0254-6051.2023.10.008

• 特约专栏 • 上一篇    下一篇

同一成分双相钢热处理与组织性能调控

张钰1, 王灵禺1, 杨凯2, 卢琦1,2, 徐伟1   

  1. 1.东北大学 轧制技术及连轧自动化国家重点实验室, 辽宁 沈阳 110819;
    2.上海理想汽车科技有限公司, 上海 201805
  • 收稿日期:2023-08-25 修回日期:2023-09-14 出版日期:2023-10-25 发布日期:2023-12-07
  • 通讯作者: 徐伟,教授,博士,E-mail:xuwei@ral.neu.edu.cn
  • 作者简介:张 钰(1998—),女,博士研究生,主要研究方向为双相钢的成分优化与组织性能调控,E-mail:2110223@stu.neu.edu.cn。
  • 基金资助:
    国家自然科学基金联合基金(U22A20106)

Heat treatment and microstructure-property regulation of dual phase steels with identical composition

Zhang Yu1, Wang Lingyu1, Yang Kai2, Lu Qi1,2, Xu Wei1   

  1. 1. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang Liaoning 110819, China;
    2. Shanghai Li Auto Technology Co., Ltd., Shanghai 201805, China
  • Received:2023-08-25 Revised:2023-09-14 Online:2023-10-25 Published:2023-12-07

摘要: 通过调控等温温度,将同一成分的低碳Si-Mn-Cr试验钢在不同的热处理工艺下实现了590、780和980 MPa 3个强度级别双相钢的制备。结果表明,随着等温温度的提高,最终室温组织中的马氏体含量增加,试验钢的抗拉强度和屈服强度随之提高,总延伸率下降。与临界等温工艺相比,加入过时效步骤后,达到相同强度时,所需要的等温温度更高,组织中的马氏体分数更高。且随着过时效温度的升高,达到相同强度级别时所需的等温温度进一步提高,马氏体分数进一步增加。利用同一合金成分,采用两种热处理工艺,都可制备590、780和980 MPa 3种不同强度级别的双相钢。但当前试验钢的合金成分采用临界等温-过时效热处理工艺时,在高强度规格(980 MPa)下其组织接近全马氏体,不符合实际双相钢的组织特性。

关键词: 双相钢, 显微组织, 力学性能, 过时效, 等温温度

Abstract: Dual phase steels with three strength levels of 590, 780 and 980 MPa were achieved simultaneously by regulating the isothermal temperature of a low-carbon Si-Mn-Cr steel under different heat treatment processes. The results show that the martensite content in the final microstructure is increased with the increase of isothermal temperature, and with a consequent increase in the tensile and yield strengths and a decrease in the total elongation of the tested steel. Compared with the intercritical isothermal process, the inclusion of the overaging step requires a higher isothermal temperature and a higher fraction of martensite in the microstructure to achieve the same strength. As the overaging temperature increases, the isothermal temperature required to reach the same strength level further increases and the martensite fraction further increases. Dual phase steels with three different strength levels of 590, 780 and 980 MPa are prepared, respectively, by using the identical composition with both heat treatment processes. However, the 980 MPa steel after the intercritical isothermal-overaging process has nearly full martensite microstructure, which does not meet the microstructure characteristics of the actual dual phase steel.

Key words: dual phase steel, microstructure, mechanical properties, overaging, isothermal temperature

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