Investigation of the porosity defect phenomenon during laser welding of powder metal material

Welding porosity is the main defect during laser welding.In this paper we briefly analyze the mechanism of engendering pores in powder metal material(PM),and study the influence of welding speed and active gas for welding porosity defect.We find that the pore number will be reduced through depressing metallic vapour if welding speed is increased with constant laser power.Using N2,O2 as active gas,the fluidity of the melting metal can be improved,so blowholes may be avoided.