Preliminary study on laser-arc hybrid additive manufacturing of austenite stainless steel

Laser-CMT (Cold Metal Transfer) arc hybrid additive manufacturing (LHAM) of 316L austenitic stainless steel (316SS) was studied. Surface roughness (R) and the minimum processing margin (d_min) of deposited thin-wall were calculated by the data measured via laser displacement sensor. Microstructure and fracture surface were observed by optical microscope and scanning electron microscope. The scanning speed of LHAM could be increased to 1.2 m/min, 3 times higher than that of wire arc additive manufacturing (WAAM). The R and d_min of LHAMed 316SS were reduced to 40% and 60% of the WAAM, respectively. The microstructure of LHAMed 316SS was composed of columnar or equiaxed grains, which were characterized by δ-ferrite and austenite. The tensile strength of LHAMed sample was higher, but the elongation is lower than that of WAAMed sample because of the formation of the porosity.