Influence of severe shot peening and Plasma spray FeCr18Ni10Mo3 coating on microstructure and mechanical properties of super austenite stainless steel sheets by laser beam welding

Abstract

In this investigation, the microstructure and mechanical properties on severe double side shot peened and Plasma Spray FeCr18Ni10Mo3 filler power coated (PSC) Super Austenite Stainless Steel (SASS) was investigated for the butt joint configuration of 2 mm thickness sheets using laser beam welding. The microstructure studies revealed the presence of more amounts of austenite elements in parent metal. Low heat input was applied in the laser welding and double side welding method was implemented. Welding parameters such as laser beam power of 900 W, welding speed of 250 mm/min and welding focus distance of 8 mm were used in the laser beam welding. The microstructure studies conducted at the fusion zone and heat affected zone revealed that the austenite boundaries were transformed into coarse grain boundaries and α′ martensite structures. The failures of all the tensile samples were observed at the fusion zone of as-welded, shot peened weldments and PS coated samples. High heat inputs implemented at the fusion zone and heat affected zone of PS coated weldments transformed α′-martensite structure into β'+β martensite and Cr + Ni grain boundaries. The average hardness value measured at fusion zone of PS coated weldments and shot peened weldments showed as 320 HV and 290 HV. Compressive residual stress analysis was performed using XRD at the fusion zone of as-weldments, shot peened weldments and PS coated weldments. The present studies conducted at the fusion zone of various weldments showed a increase in the corrosion resistance and improved the tensile and bending properties.