对比研究了焊前和焊后调质处理条件下25Cr2Ni4MoV钢焊接接头的显微组织、力学性能和耐腐蚀性能，调质处理工艺为920℃×1 h油淬+580℃×2 h回火，焊接工艺为手工焊条电弧焊。结果表明：焊前调质处理的接头焊缝组织为板条马氏体+δ-铁素体+M₂₃C₆碳化物，焊后调质处理使焊缝中的δ-铁素体溶解，形成了板条马氏体+回火索氏体+M₂₃C₆碳化物；焊后调质处理条件下，焊缝中的板条马氏体细小均匀，M₂₃C₆碳化物呈颗粒状分布于原奥氏体晶界和马氏体板条晶界处，焊缝的强度、冲击韧性和耐腐蚀性能均优于焊前调质处理的。

Microstructure, mechanical properties and corrosion resistance of 25Cr2Ni4MoV steel welded joint were compared and studied under conditions of pre-welding and post-welding quenching and tempering treatments. The quenching and tempering process was oil quenching at 920 ℃ for 1 h and tempering at 580 ℃ for 2 h. The welding process was manual electrode arc welding. The results show that by pre-welding quenching and tempering, the microstructure of the joint weld zone consisted of lath martensite, network δ-ferrite and M₂₃C₆ carbide. After the post-welding quenching and tempering, the δ-ferrite in the weld was dissolved, and the lath martensite, tempered sorbite and M₂₃C₆ carbide were formed. Under the post-welding quenching and tempering condition, the lath martensite in the weld was small and uniform, and the M₂₃C₆ carbide distributed in granular shapes on original austenite grain boundaries and martensite lath grain boundaries; the strength, impact toughness and corrosion resistance were better than those by the pre-welding quenching and tempering treatment.