• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2023, Vol. 59 ›› Issue (4): 34-42.doi: 10.3901/JME.2023.04.034

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Microstructure Strengthening Mechanism of Surface Layer of Ultra-high Strength Steel by Thermal Assisted Ultrasonic Rolling

LUAN Xiaosheng1, LIANG Zhiqiang2, ZHAO Wenxiang2, XIAO Shihong1,3, ZHOU Tianfeng2, WANG Xibin2, LI Hongwei4, LIU Xinli4, LIU Zhenni4   

  1. 1. School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081;
    2. Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, Beijing 100081;
    3. AVIC Manufacturing Technology Institute, Beijing 100024;
    4. Beijing North Vehicle Group Corporation, Beijing 100072
  • Received:2022-03-16 Revised:2022-05-20 Online:2023-02-20 Published:2023-04-24

Abstract: To deal with the problems of poor cold plastic deformation ability and difficult surface deformation strengthening of ultra-high strength steel, a thermal assisted ultrasonic rolling surface strengthening method is proposed. The surface thermal assisted ultrasonic rolling test of 45CrNiMoVA steel was carried out. The evolution and strengthening mechanism of surface microstructure were characterized and analyzed by SEM, EBSD, and TEM, combined with the residual stress distribution results of the surface layer. It is found that under the coupling effect of acoustic softening and thermal softening, the plastic deformation degree of 45CrNiMoVA steel surface material is intensified, the depth of plastic deformation layer is increased, the grain refinement of surface material occurs, and the microstructure with gradient distribution of grain size along the depth direction is formed. Fine-grain strengthening and dislocation strengthening are the main strengthening mechanisms. The effectiveness of the thermal assisted ultrasonic rolling method is proved, which is of great significance to the development of surface strengthening technology of ultra-high strength steel parts.

Key words: thermal assisted ultrasonic rolling, ultra-high strength steel, microstructure, surface strengthening

CLC Number: