Microstructure and mechanical properties of austenite stainless steel wire joints welded by laser

Austenite stainless steel thin wires were joined by using pulsed YAG laser welding.The microstructural characteristics and influences of laser welding parameters on microstructures and mechanical properties of joints were investigated by means of optical microscopy and scanning electronic microscopy et al.Experimental results show that the fusion zone features cellular and cellular-dendrite crystal structure,HAZ mainly exhibits equiaxed crystals,and near the fusion zone the equiaxed crystals coarsen.With the increase of power input and pulse duration for laser,the penetration ratio and melted metal width increase,and microstructures of the weld metal and HAZ have coarsening tendency.It is unfavorable to select short pulse duration(2 ms,3 ms)for controlling welding quality.The highest tensile strength of laser-welded joints reaches to 680 MPa(pulse duration of 10 ms and power input of 7.6 J),the weld centre being the weakest region in the joints.