焊前和焊后调质处理下25Cr2Ni4MoV钢焊接接头的组织及性能

Microstructure and Properties of 25Cr2Ni4MoV Steel Welded Joint under Pre-welding and Post-welding Quenching and Tempering Treatment

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℃×1h油淬+580℃×2h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+M_(23)C_(6)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+M_(23)C_(6)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,M_(23)C_(6)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 25Cr2Ni4 MoV 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 M_(23)C_(6) carbide.After the post-welding quenching and tempering,theδ-ferrite in the weld was dissolved,and the lath martensite,tempered sorbite and M_(23)C_(6) carbide were formed.Under the post-welding quenching and tempering condition,the lath martensite in the weld was small and uniform,and the M_(23)C_(6) 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.