Investigation the Microstructure and Mechanical Properties of 17-7 PH Stainless Steel Welded by Pulsed Nd-YAG Laser Beam

In this research, the metallurgical investigation of the welding of 17-7 PH steel using the Nd: YAG pulsed laser welding process was conducted. The effect of parameters such as welding speed, laser pulse width and power on welding geometry was evaluated. The microstructure and fracture surface of weld samples were studied using the optical microscope and scanning electron microscope (SEM). Also, in order the tensile, microhardness and impact tests were used to study the mechanical behavior of the joint. It was found that the microstructure of the weld metal of the samples contained skeletal and lathy ferrite as well as austenite. The maximum tensile strength was observed in the sample with power 300, welding speed 2 and pulse width 3.5, and the minimum tensile strength was observed in the sample with power 300, welding speed 2 and pulse width 3. The SEM images of the tensile cross section showed that the failure occurred in all the soft samples. As a result, in this study, the best mechanical and microstructural results were obtained in the welded sample with optimal parameters including power 300, welding speed 2 and pulse width 3.5.