Investigation of tensile and fatigue properties of an austenitic stainless steel part fabricated by WAAM

Abstract

Austenitic stainless steels are used in many industrial applications and the use of components produced from this material by the wire arc additive manufacturing (WAAM) method has gained interest. Since damage of metallic parts generally occurs due to fatigue, it is necessary to understand their fatigue properties. This study focused on the determination of tensile and fatigue properties of an austenitic stainless steel structure produced by WAAM. For this purpose, a medium-sized part was fabricated using 308LSi metallic wire and gas metal arc welding (GMAW) technique. Hardness tests and microstructure examinations were also performed on the part. In the tensile tests, it was found that the strength and ductility of the vertical and horizontal samples were different. However, the fatigue test results of horizontal and vertical specimens were very similar. The average fatigue limit was found to be 195 MPa, and the fatigue life of the sample reached 107 without any macro damage. As a result of the hardness tests, the average hardness was calculated as 197 HV0.5. In the microstructure studies, different ferrite formations were observed in the austenite matrix on the bottom, middle and upper zones. The changes in microstructure were mostly attributed to the exposure of multiple layers to different heating and cooling rates during WAAM.