Heat Treatment of Metals ›› 2025, Vol. 50 ›› Issue (5): 86-93.DOI: 10.13251/j.issn.0254-6051.2025.05.014

• MATERIALS RESEARCH • Previous Articles     Next Articles

Phase transformation characteristics of martensitic stainless steel 4Cr13Cu

Guo Jingen1, Liang Aiwu1, Chen Xuan2, Wu Minghui2, Mao Xinguo2, Zhai Qinghua2, Miao Jingjing2, Ge Yongxin2   

  1. 1. Research Center of Grid Planning, Guangdong Power Grid Co., Ltd., Guangzhou Guangdong 510080, China;
    2. Jiangsu Zhongtian Technology Co., Ltd., Nantong Jiangsu 226463, China
  • Received:2024-11-06 Revised:2025-03-06 Published:2025-06-25

Abstract: Continuous cooling transformation behavior and isothermal transformation kinetics of undercooled austenite of a newly developed martensitic stainless steel 4Cr13Cu at different cooling rates were studied. The linear expansion behavior of the 4Cr13Cu steel was measured by DIL805A high-precision differential thermal dilatometer, and the cooling transformation products were analyzed by OM and SEM. According to the JMA formula, the activation energy and Avrami index of pearlite isothermal phase transformation in 4Cr13Cu steel were calculated. The results show that during the continuous cooling process of undercooled austenite of the 4Cr13Cu steel, when the cooling rate is greater than 0.1 ℃/s, the transformation product is full martensite. When the cooling rate is less than 0.1 ℃/s, the transformation product is a mixture of martensite and pearlite, and the content of pearlite increases with the decrease of cooling rate. The isothermal transformation range of pearlite in the 4Cr13Cu steel is 600-680 ℃, and the nose transformation temperature is about 635 ℃. The calculated values of JMA equations under different isothermal conditions are in good agreement with the measured values. The activation energy of pearlite transformation is about 93.1 kJ/mol, and the Avrami index n is in the range of 1.5-2.5, the nucleation rate of pearlite decreases with the prolongation of isothermal time.

Key words: martensitic stainless steel 4Cr13Cu, cooling rate, continuous cooling transformation, isothermal transformation

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