金属热处理 ›› 2025, Vol. 50 ›› Issue (7): 204-211.DOI: 10.13251/j.issn.0254-6051.2025.07.029

• 材料研究 • 上一篇    下一篇

控轧控冷工艺对3.5%Ni耐候钢组织与性能的影响

付天乐1,2, 沙莎1,2, 汪兵1, 陈小平1   

  1. 1.钢铁研究总院有限公司 工程用钢研究院, 北京 100081;
    2.中国石油大学(北京) 新能源与材料学院, 北京 102200
  • 收稿日期:2025-01-06 修回日期:2025-04-18 出版日期:2025-07-25 发布日期:2025-07-28
  • 通讯作者: 汪兵,教授,博士,E-mail:wbgyzy@126.com
  • 作者简介:付天乐(1999—),男,硕士研究生,主要研究方向为海洋大气耐候钢,E-mail:2389901469@qq.com。
  • 基金资助:
    十四五国家重点研发计划-海洋建筑结构用钢失效机理及材料设计(2021YFB3701701)

Effect of thermomechanical control process on microstructure and properties of weathering steel containing 3.5%Ni

Fu Tianle1,2, Sha Sha1,2, Wang Bing1, Chen Xiaoping1   

  1. 1. Research Institute of Structural Steels, Central Iron and Steel Research Institute Co., Ltd., Beijing 100081, China;
    2. College of New Energy and Materials, China University of Petroleum (Beijing), Beijing 102200, China
  • Received:2025-01-06 Revised:2025-04-18 Online:2025-07-25 Published:2025-07-28

摘要: 采用Gleeble-3800热力学模拟试验机,结合Thermo-Calc热力学计算、组织观察和硬度测量,对3.5%Ni耐候钢的过冷奥氏体连续冷却转变行为进行了研究,绘制了动态CCT曲线,并制定了控轧控冷工艺(TMCP)。结果表明,试验钢的Ac1和Ac3温度分别为625 ℃和776 ℃。冷速在1 ℃/s及以下时,组织为粒状贝氏体和少量铁素体与珠光体的混合组织;当冷速为2~5 ℃/s时,组织为完全粒状贝氏体;冷速为10 ℃/s时,组织为粒状贝氏体+板条贝氏体,冷速达到20 ℃/s及以上时,组织为完全板条贝氏体。根据动态CCT曲线和Cu元素析出特征,制定了控轧控冷工艺。与原轧制工艺相比,控轧控冷工艺生产的试验钢原奥氏体晶粒和组织均细化,M/A岛尺寸和含量大幅度降低,在强度基本相当的情况下,室温冲击吸收能量显著增加至105 J左右。与此同时,断后伸长率和断面收缩率也得到改善。

关键词: 耐侯钢, 动态CCT曲线, 显微组织, 硬度, 控轧控冷工艺

Abstract: Continuous cooling transformation behavior of supercooled austenite in 3.5%Ni weathering steel was studied by using Gleeble-3800 thermomechanical simulation testing machine, combined with Thermo-Calc thermodynamics calculations, microstructure observation, and hardness measurement. Dynamic CCT curve was plotted, and thermomechanical control process(TMCP) was developed. The results show that the Ac1 and Ac3 temperatures of the tested steel are 625 ℃ and 776 ℃, respectively. When the cooling rate is 1 ℃/s or lower, the microstructure consists of granular bainite mixed with small amounts of ferrite and pearlite. At cooling rates between 2 ℃/s and 5 ℃/s, the microstructure transforms to entirely granular bainite. When the cooling rate reaches 10 ℃/s, the microstructure becomes a mixture of granular bainite and lath bainite. At cooling rates of 20 ℃/s and above, the microstructure is composed entirely of lath bainite. According to the dynamic CCT curve and the precipitation characteristics of Cu element, thermomechanical control process was formulated. Compared with the original rolling process, the grain size of prior austenite and microstructure of the tested steel produced by thermomechanical control process are refined, and the size and content of M/A islands are significantly reduced. Under the condition of basically equivalent strength, the impact absorbed energy at room temperature significantly increases to about 105 J. At the same time, the elongation after fracture and reduction of area are also improved.

Key words: weathering steel, dynamic CCT curve, microstructure, hardness, thermomechanical control process

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