20钢-Q345C管接头超窄间隙激光填丝焊研究

Research on the ultra-narrow gap laser wire filler welding for the 20 steel-Q345C pipe welded joints

采用超窄间隙激光填丝焊技术焊接中厚钢板,可通过填充金属来改变焊缝区的成分与组织,使焊缝成分的调整更加方便,从而提高接头的综合性能。以20钢-Q345C管为研究对象,采用超窄间隙激光焊进行焊接工艺试验,研究焊接接头的拉伸强度、弯曲性能、冲击强度以及微观组织。结果表明:焊接接头的拉伸强度、弯曲性能、冲击性能均符合标准要求;由于激光自熔焊热输入较大,冷却速度快,有淬硬倾向,所以焊缝硬度最高;热影响区中组织主要为魏氏组织,而焊缝中心主要成分则是沿晶界析出的先共析铁素体以及晶界内的针状铁素体+珠光体。母材组织由片状珠光体和铁素体组成,因此超窄间隙激光填丝焊技术焊接20钢-Q345C管具有较好的工程应用价值。

The welding technology of ultra-narrow gap wire filler welding could improve the general properties of welded joints when the filler metals could change the microstructure and chemical elements.This paper focused on the 20 steel-Q345C pipe welded joints properties which welded with the ultra-narrow gap wire filler welding and the tensile strength,bending properties,impact properties and microstructure were studied.The results showed that the tensile strength,bending properties and impact toughness were all in accordance with the standard.Because the higher heat input and faster cooling speed with quench trend then the weld showed the highest microhardness.The microstructure of HAZ was composed of Widmanstatten structure,while the main components of the weld center were proeutectoid ferrite precipitated along grain boundary and acicular ferrite and pearlite in grain boundary.The microstructure of the base metal was lamellar pearlite and ferrite.So the ultra-narrow gap laser wire-filling welding technology for 20 steel-Q345C pipe has good engineering application value.