Heat Treatment of Metals ›› 2023, Vol. 48 ›› Issue (10): 168-174.DOI: 10.13251/j.issn.0254-6051.2023.10.025

• PROCESS RESEARCH • Previous Articles     Next Articles

Local induction tempering process of 30CrMnSiNi2A steel threaded parts

Wang Haojun1, Yang Ping1, Ren Shufeng2, Luo Xian2, Ran Gang2   

  1. 1. Avic Xi'an Aircraft Industry Group Co., Ltd., Xi'an Shaanxi 710089, China;
    2. School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an Shaanxi 710072, China
  • Received:2023-04-13 Revised:2023-07-27 Online:2023-10-25 Published:2023-12-07

Abstract: Local induction tempering process of 30CrMnSiNi2A steel threaded specimen was studied. The effects of different pre-treatment (isothermal quenching+low temperature tempering and vacuum oil quenching+low temperature tempering) and different induction tempering processes (single-stage heating, two-stage heating and two-stage heating+temperature compensation by moving) on the hardness distribution of the specimen after tempering were investigated. The results show that the difference of hardness and microstructure of the specimen pre-treated by isothermal quenching plus low temperature tempering and vacuum oil quenching plus low temperature tempering are not obvious. Due to the skin effect and end effect, large radial and axial hardness gradients is produced in the specimens by single-stage induction heating. The two-stage heating can eliminate the radial hardness gradient caused by skin effect by adding a uniform temperature time, and the axial hardness gradient caused by end effect can be eliminated through temperature compensation by moving the sensor. The hardness at the thread end of the specimen uniformly distributed within the required range can be obtained by the induction tempering process of two-stage heating+temperature compensation by moving.

Key words: 30CrMnSiNi2A steel, induction heat treatment, induction tempering, temperature field, hardness

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