J. Mater. Sci. Technol. ›› 2017, Vol. 33 ›› Issue (12): 1448-1456.DOI: 10.1016/j.jmst.2017.01.025

• Orginal Article • Previous Articles     Next Articles

Precipitation and hot deformation behavior of austenitic heat-resistant steels: A review

Zhou Yinghuiab, Liu Yongchangac*(), Zhou Xiaoshenga*(), Liu Chenxia, Yu Jianxinac, Huang Yuana, Li Huijuna, Li Wenyab   

  1. aState Key Lab of Hydraulic Engineering Simulation and Safety, School of Materials Science & Engineering, Tianjin University, Tianjin 300354, China
    bSchool of Materials Science & Engineering, Northwestern Polytechnical University, Xi’an 710072, China
    cCollaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2016-11-22 Revised:2016-12-23 Accepted:2016-12-26 Online:2017-12-20 Published:2018-01-30
  • Contact: Liu Yongchang,Zhou Xiaosheng

Abstract:

The austenitic heat resistant-steels have been considered as important candidate materials for advanced supercritical boilers, nuclear reactors, super heaters and chemical reactors, due to their favorable combination of high strength, corrosion resistance, perfect mechanical properties, workability and low cost. Since the precipitation behavior of the steels during long-term service at elevated temperature would lead to the deterioration of mechanical properties, it is essential to clarify the evolution of secondary phases in the microstructure of the steels. Here, a summary of recent progress in the precipitation behavior and the coarsening mechanism of various precipitates during aging in austenitic steels is made. Various secondary phases are formed under service conditions, like MX carbonitrides, M23C6 carbides, Z phase, sigma phase and Laves phase. It is found that the coarsening rate of M23C6 carbides is much higher than that of MX carbonitrides. In order to understand the thermal deformation mechanism, a constitutive equation can be established, and thus obtained processing maps are beneficial to optimizing thermal processing parameters, leading to improved thermal processing properties of steels.

Key words: Austenitic steels, Coarsening behavior, Hot deformation, Microstructure