J. Mater. Sci. Technol. ›› 2018, Vol. 34 ›› Issue (4): 653-659.DOI: 10.1016/j.jmst.2017.11.031

• Orginal Article • Previous Articles     Next Articles

Microstructure evolution and mechanical properties of linear friction welded S31042 heat-resistant steel

Yanmo Lia, Yongchang Liua*(), Chenxi Liua, Chong Lia, Zongqing Maa*(), Yuan Huanga, Zumin Wanga, Wenya Lib   

  1. aState Key Lab. of Hydraulic Engineering Simulation and Safety, School of Materials Science and Engineering, Tianjin University, Tianjin 300354, China
    bSchool of Materials Science and Engineering, Northwestern Polytechnical University, Xian 710072, China
  • Received:2017-03-26 Revised:2017-07-07 Accepted:2017-07-11 Online:2018-04-20 Published:2018-05-04
  • Contact: Liu Yongchang,Ma Zongqing

Abstract:

S31042 heat-resistant steel was joined by linear friction welding (LFW) in this study. The microstructure and the mechanical properties of the LFWed joint were investigated by optical microscopy, scanning electronic microscopy, transmission electron microscopy, hardness test and tensile test. A defect-free joint was achieved by using LFW under reasonable welding parameters. The dynamic recrystallization of austenitic grains and the dispersed precipitation of NbCrN particles resulting from the high stress and high temperature in welding, would lead to a improvement of mechanical property of the welded joint. With increasing the distance from the weld zone to the parent metal, the austenitic grain size gradually increases from?~1 μm to ~150 μm, and the microhardness decreases from 301 HV to 225 HV. The tensile strength (about 731 MPa) of the welded joint is comparable to that of the S31042 in the solution-treated state.

Key words: Austenitic steel, Welding, Microstructure, Mechanical property, Precipitation