Heat Treatment of Metals ›› 2025, Vol. 50 ›› Issue (5): 253-257.DOI: 10.13251/j.issn.0254-6051.2025.05.039

• PROCESS RESEARCH • Previous Articles     Next Articles

Influence of quenching cooling rate on microstructure and properties of vanadium and niobium microalloyed cast steel brake disc

Zhu Jiaqi1,2, Jiao Biaoqiang1,2, Lü Baojia1,2, Cai Tian1,2, Tan Zhunli3   

  1. 1. Locomotive & Car Research Institute, China Academy of Railway Sciences Corporation Limited, Beijing 100081, China;
    2. Beijing Zongheng Electro-Mechanical Technology Co., Ltd., Beijing 100094, China;
    3. School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044, China
  • Received:2024-12-07 Revised:2025-04-02 Published:2025-06-25

Abstract: Quenching and tempering treatments were carried out on V and Nb microalloyed high-speed railway cast steel brake discs at different quenching cooling rates. Combined with the continuous cooling transformation curves, the differences in microstructure and mechanical properties and its mechanism of the tested cast steel were compared and analyzed. The results show that a large quantity of bainite in the microstructure appear when using a slower cooling rate quenching medium, which differs greatly from the matrix of tempered martensite and leads to the brittleness. While under higher cooling rate quenching media, the cast steel brake disc obtains a completely tempered martensite. When using a cooling medium with a maximum cooling rate of 140-165 ℃/s and a cooling rate of 40-60 ℃/s at 300 ℃ for quenching, the optimal comprehensive mechanical properties can be obtained for the tested V and Nb microalloyed high-speed railway cast steel brake disc.

Key words: cast steel brake disc, vanadium, niobium, quenching cooling rate, microstructure, properties

CLC Number: