Effects of Aging at 550℃ on α'-Martensitic Transformation of High Si-Bearing Metastable Austenitic Stainless Steel Weld Metal  

作　　者：Yakui Chen Shitong Wei Dong Wu Shanping Lu 

机构地区：[1]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang,110016,China [2]School of Materials Science and Engineering,University of Science and Technology of China,Shenyang,110016,China [3]CAS Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang,110016,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2024年第9期1467-1479,共13页金属学报（英文版）

基　　金：supported by the National Key Research and Development Program of China(2018YFA0702902);the Innovation Project of Shenyang National Laboratory for Materials Science(SYNL-2022);the China Institute of Atomic Energy(E141L803J1).

摘　　要：The high Si-bearing 15Cr-9Ni-Nb metastable austenitic stainless steel weld metal was prepared via gas tungsten arc welding and then processed by stabilized heat treatment(SHT)at 850℃ for 3 h.The effects of 550℃ aging on the α'-martensitic transformation of the as-welded and the SHT weld metals were investigated.The results showed that the weld metal had poor thermal stability of austenite.The precipitation of NbC during the 850℃ SHT made the thermal stability of the local matrix decrease and led to the formation of a large amount of C-depleted α'-martensite.The precipitation of coarse σ-phase at the δ-ferrite led to the Cr-depleted zone and the formation of Cr-depleted α'-martensite at the early stage of 550℃ aging.The homogenized diffusion of C and Cr in the matrix during 550℃ aging led to the restoration of austenitic thermal stability and the decrease of α'-martensite content.The C-depleted α'-martensite content in the SHT weld metal decreased rapidly at the early stage of aging due to the fast diffusion rate of the C atom in the matrix,while the Cr-depleted α'-martensite decreased at the later stage of aging due to the decreased diffusion rate of the Cr.

关 键 词：Metastable austenitic stainless steel weld metal α'-martensitic transformation Δ-FERRITE σ-phase 

分 类 号：TG142.71[一般工业技术—材料科学与工程]