金属热处理 ›› 2025, Vol. 50 ›› Issue (1): 68-74.DOI: 10.13251/j.issn.0254-6051.2025.01.011

• 工艺研究 • 上一篇    下一篇

连续退火热镀锌工艺对含铌DP780双相钢组织与性能的影响

任宇鹏1, 张鹤松2, 李声慈1, 刘维朋1, 富聿晶3   

  1. 1.江西理工大学 材料科学与工程学院, 江西 赣州 341000;
    2.钢铁研究总院有限公司 工程用钢研究院, 北京 100081;
    3.本钢集团有限公司 技术中心, 辽宁 本溪 117000
  • 收稿日期:2024-08-12 修回日期:2024-11-13 出版日期:2025-01-25 发布日期:2025-03-12
  • 通讯作者: 李声慈,副教授,博士,E-mail:lishengci1988@163.com
  • 作者简介:任宇鹏(1996—),男,硕士研究生,主要研究方向为双相钢的组织性能,E-mail:870673625@qq.com。
  • 基金资助:
    赣鄱俊才支持计划-主要学科学术和技术带头人培养项目(20232BCJ23002);江西理工大学清江青年优秀人才支持计划(JXUSTQJYX2020011)

Effect of continuous annealing hot-dip galvanizing process on microstructure and properties of a niobium-containing DP780 steel

Ren Yupeng1, Zhang Hesong2, Li Shengci1, Liu Weipeng1, Fu Yujing3   

  1. 1. School of Materials Science and Engineering, Jiangxi University of Science and Technology, Ganzhou Jiangxi 341000, China;
    2. Research Institute of Engineering Steels, Central Iron and Steel Research Institute Co., Ltd., Beijing 100081, China;
    3. Technical Center, Benxi Steel Group Co., Ltd., Benxi Liaoning 117000, China
  • Received:2024-08-12 Revised:2024-11-13 Online:2025-01-25 Published:2025-03-12

摘要: 利用热镀锌模拟试验机研究了780 MPa级双相钢连续退火热镀锌过程,对比分析了直接淬火、缓冷后淬火、镀前马氏体工艺和镀后马氏体工艺对试验钢显微组织及拉伸性能的影响。结果表明:试验钢在两相区加热后的缓冷过程可以提高未转变奥氏体淬透性,得到稳定性高的岛状马氏体;镀前马氏体工艺下钢中出现了少量回火马氏体,Nb可以提高马氏体的回火稳定性,改善热镀锌双相钢的力学性能;镀后马氏体工艺和镀前马氏体工艺下钢中的析出相特征没有变化,富Nb析出相容易在先析出的TiN界面进行异质形核析出;镀前马氏体工艺获得的双相钢抗拉强度为867 MPa,伸长率为21.3%,与镀后马氏体工艺的抗拉强度(878 MPa)和伸长率(24.0%)接近;但镀前马氏体工艺获得的双相钢屈服强度(564 MPa)则较镀后马氏体工艺(611 MPa)明显减小。因此,镀前马氏体工艺可以在保证双相钢强塑性的同时,有效降低双相钢的屈强比,改善其成形性能。

关键词: 双相钢, 热镀锌, 马氏体, 连续退火

Abstract: Continuous annealing hot-dip galvanizing process of a 780 MPa grade dual phase (DP) steel was studied by using hot-dip galvanizing simulation testing machine. Effects of four different heat treatment processes as direct quenching, quenching after slow cooling, post-galvanized martensite process and pre-galvanized martensite process on the microstructure and tensile properties of the steel were compared and analyzed. The results show that the slow cooling process after heating in the two-phase region can improve the hardenability of the untransformed austenite and obtain stable island-like martensite. A small amount of tempered martensite is obtained by the pre-galvanized martensite process. The Nb can improve the tempering stability of martensite and improve the mechanical properties of hot-dip galvanized DP steel. There is no significant change in precipitated phases of the steel after the post-galvanized martensite process and the pre-galvanized martensite process, the Nb-rich precipitates are prone to heterogeneous nucleation and precipitation at the interface of TiN precipitated firstly. The tensile strength of the DP steel obtained by the pre-galvanized martensite process is 867 MPa, and the elongation is 21.3%, which is close to the tensile strength (878 MPa) and elongation (24.0%) of the post-galvanized martensite process. However, the yield strength of the DP steel obtained by the pre-galvanized martensite process (564 MPa) is significantly reduced compared to the post-galvanized martensite (611 MPa). Therefore, the pre-galvanized martensite process can effectively reduce the yield ratio and improve the formability of the dual phase steel while ensuring its strength and plasticity.

Key words: dual phase steel, hot-dip galvanizing, martensite, continuous annealing

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