Acta Metallurgica Sinica (English Letters) ›› 2019, Vol. 32 ›› Issue (9): 1151-1160.DOI: 10.1007/s40195-019-00883-6

Special Issue: 2019年钢铁材料专辑

• Orginal Article • Previous Articles     Next Articles

Effects of Isothermal Aging on Microstructure and Mechanical Property of Low-Carbon RAFM Steel

Jian-Guo Chen1,2, Chen-Xi Liu1(), Chen Wei2, Yong-Chang Liu1(), Hui-Jun Li1   

  1. 1.State Key Lab of Hydraulic Engineering Simulation and Safety, School of Materials Science and Engineering, Tianjin University Tianjin 300350, China
    2.Tianjin Special Equipment Inspection, Institute Tianjin 300192, China
  • Received:2018-10-13 Revised:2018-11-06 Online:2019-09-10 Published:2019-08-06

Abstract:

In order to investigate the microstructure and mechanical property evolution of low-carbon reduced activation ferritic/martensitic (RAFM) steel during isothermal aging, the normalized and tempered specimens were aged at 600 °C for 500, 1000, and 3000 h, respectively. The microstructural evolution with aging time was analyzed, including the precipitation and growth of M23C6 and MX-type carbides as well as the formation of Laves phase. The results indicate that the coarsening of M23C6 is more obvious than that of MXwith increase in aging time. During the long-term thermal exposure, the Fe2W Laves phase precipitates adjacent to M23C6 along the prior austenite grain boundaries and packet boundaries. Lower carbon content can delay the precipitation of Laves phase compared to the steel containing higher carbon. In addition, the Laves phase precipitated along boundaries can provide the precipitation strengthening, slightly increasing the tensile strength of low-carbon RAFM steel after aging for 3000 h.

Key words: Low-carbon RAFM steel, Isothermal aging, Microstructure evolution, Mechanical property