Eutectic precipitates and microstructure of electroslag remelted 15Cr-22Ni austenitic heat-resistant steel with varying Nb contents  

作　　者：Hao-chi Xu Cheng-bin Shi Xin Zhu Shi-jun Wang Jing Li Shi-zhou Wang 

机构地区：[1]State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing(USTB),Beijing 100083,China

出　　处：《Journal of Iron and Steel Research International》2022年第11期1823-1835,共13页

基　　金：support by the National Natural Science Foundation of China(Grant Nos.51874026 and 52074027);the financial support from the State Key Laboratory of Advanced Metallurgy(Grant No.41621024).

摘　　要：The microstructure,eutectic carbides and intermetallic compounds in as-cast ingots with varying Nb contents produced by electroslag remelting were studied.The solidification behavior,microsegregation of alloying elements and its influence on precipitates were analyzed.The increase in Nb content from 0.64 to 1.40 wt.%has no effect on the dendrite morphology and secondary dendrite arm spacing.The total area fraction of eutectic NbC and Laves phase in as-cast ingots increases with the increase in Nb content.The eutectic precipitates in the ingot with 0.64 wt.%Nb are mainly NbC,and the others are Fe_(2)Nb-type Laves phase.Increasing the Nb content of the steel significantly promotes the precipitation of Laves phases and lowers the precipitation temperature of NbC eutectic carbides.Eutectic carbide M_(2)C is precipitated only in the ingot with 1.4 wt.%Nb.The average concentration of Nb in both interdendritic and intragranular regions increases with the increase in Nb content of the steel,leading to a change in the morphology of Fe_(2)Nb-type Laves phase from honeycomb to blocky.Increasing the Nb content exerts little effect on the microsegregation degrees of Si,Mo,Cr and Ni in the steel.

关 键 词：Eutectic carbides Fe2Nb-type Laves phase Austenitic heat-resistant steel MICROSEGREGATION Electroslag remelting 

分 类 号：TG14[一般工业技术—材料科学与工程]