众所周知,紫铜具有较高的导热性和大的热容量,焊接时要求很大的热源,在手工电弧焊接紫铜时必须预热,因此热影响区增大。由于加热时间较长,使铜氧化,并且在焊接时容易吸收有害气体,使焊缝出现气孔、裂缝等缺陷。另外铜在加热时无再结晶过程,使热影响区组织晶粒粗大,而降低焊缝的机械性能。因此该材 As we all know, copper has high thermal conductivity and large heat capacity, welding requires a lot of heat source, in the manual arc welding of copper must be preheated, so the HAZ increases. Due to the heating time is longer, so that copper oxidation, and easy to absorb harmful gases in the weld, the weld appears pores, cracks and other defects. In addition, there is no recrystallization of copper during heating, so that the coarse grains in the HAZ are coarsened and the mechanical properties of the weld are reduced. So the material