焊接热循环对含铜时效钢HAZ组织与力学性能的影响

Effect of welding thermal cycle on HAZ microstructure and mechanical properties of copper-bearing age-hardening steels

研究了焊接热循环对含铜时效钢焊接热影响区组织与性能的影响。结果表明,经历单次热循环后,含铜时效钢焊接热影响区不同区域性能存在显著差异。粗晶区冲击韧度最差,这主要是奥氏体的晶粒长大及粒状贝氏体的增多所致;两相区是热影响区的“软化区”,母材中析出相的粗化及重溶和铁素体量的增多是导致两相区硬度降低的主要原因。二次热循环对模拟HAZ组织和性能有显著影响,粗晶区+两相区是二次热循环中性能最差的区域。基体中部分析出物的粗化或回溶以及组织中铁素体量的增加是导致两相区硬度降低的主要原因;大尺寸粒状贝氏体的增多是导致该区域韧性下降的主要原因。

Effect of welding thermal cycle on microstructure and mechanical properties of copper-bearing age hardening steel were studied. The results showed that there was significant difference on mechanical properties in different region of HAZ after single welding thermal cycle. Coarse-grain region has the poor impact toughness in HAZ because of growth of austenite grain and increasing amount of granular-binaite. Intercritical region is the softened region in HAZ which is due to coarsening and redissolving of precipitate phase and increasing amount of ferrite. Double thermal cycle has great impact toughress on HAZ microstructures and properties. CGHAZ+ICHAZ is region which has the worst mechanic properties after double thermal cycle because of increase of amount and size of granular bainite.