Study on the fiber laser/TIG weldability of AISI 304 and AISI 410 dissimilar weld

Abstract

In this study, AISI 304 and AISI 410 stainless steels were welded together by a fiber laser-TIG hybrid welding system. Weldability was evaluated through the characterization of the microstructure and mechanical properties. The effects of welding parameters, such as laser line energy (ratio between laser power and feed rate) and arc current, were analyzed. Welds microstructure and defects were assessed and related to the tensile test, type of fracture and residual stress. The latter was measured in the normal and longitudinal directions respect to the weld line. The difference observed in the two sides of the weld were highlighted and commented. FZ microstructure resulted predominantly martensitic, which increased the micro-hardness up to an average value of about 350 HV. Porosity reached a minimum, about 0.2%, when the maximum values were used for laser line energy and arc current. Maximum elongation was as far as 4.87% and the tensile strength as big as 391 MPa. Residual stresses were much lower than the ultimate tensile and yield stresses. Eventually, the paper demonstrated the good and easy weldability of dissimilar austenitic and martensitic stainless steels in annealed condition by fiber laser coupled with an electric arc.