GX12CrMoVNbN10-1-1耐热铸钢焊接接头微观组织及力学性能研究

Study on Microstructure and Mechanical Properties of GX12CrMoVNbN10-1-1 Heat Resistant Cast Steel Welded Joint

采用窄间隙钨极气体保护焊对GX12CrMoVNbN10-1-1耐热铸钢进行了焊接试验。通过金相试验、硬度测试、拉伸试验研究了焊接接头的显微组织和拉伸性能。结果显示:焊接接头各区域的显微组织差异明显,焊缝由于形成马氏体组织,显微硬度最大,热影响区的组织主要为回火马氏体,硬度降低。接头的屈服强度高于母材,但抗拉强度略低于母材;母材及接头的屈服强度和抗拉强度均随应变速率的增加而增加,但二者的伸长率变化不大,接头的伸长率比母材的小。

The welding test of GX12CrMoVNbN10-1-1 heat resistant cast steel was carried out by using narrow gap tungsten gas shield welding technology. The microstructure and tensile properties of the welded joint were tested through metallurgical test, micro-hardness test and tensile test. The results show that the microstructure of each region in the welded joint is obviously different. The microhardness of weld zone is maximum due to the formation of martensite structure, while the microhardness heat affected zone （HAZ） decreases due to that the microstructure of HAZ is tempered martensite. The yield strength of the joint is higher than that of base metal, while the ultimate tensile strength of the joint is lower than that of base metal. As for the base metal and joint, both yield strength and ultimate tensile strength increase with the increase of strain rate, while the elongation of the two changes little, and the elongation of the joint is lower than that of base metal.