Investigation of microstructure and mechanical properties of AISI304L Stainless Steel to ASTMA514 Steel joint by Gas Tungsten Arc Welding

In the present study, Dissimilar welding of austenitic stainless steel AISI 304L to Quenched and Tempered Steel ASTM A514 was investigated by gas tungsten arc welding process. Two filler metals including (ERNiCr-3) and austenitic stainless steel 309l (ER309L) were used. Microstructure of nugget, heat affected zone, inter face and unmixed zone (UMZ) was studied by optic microscopy and scanning electron microscopy equipped with energy disperse spectrometry (EDS). The investigations showed completely austenitic structure as dendrite for ERNiCr-3 weld metal and primary ferrite with austenitic matrix for 309l weld metal. Mechanical properties including tensile and bending strength, impact resistance, hardness and fractography of the specimen was studied. The entire specimen underwent ductile fracture in HAZ in the tension test. Tensile strength in ER309L and ERNiCr-3 had increment of 556 Mpa and 593 Mpa respectively. Impact thoughtless in join induced by ERNiCr-3 filler was 117 J while it was 95 J for ER309L. The maximum and minimum hardness was related to the ERNiCr-3 (156 Vickers) and ER309L (127 Vickers), respectively. Finally, according to mechanical properties, it can be concluded that in dissimilar welding of austenitic stainless steel AISI 304 L to Quenched- Tempered Steel ASTM A514, The ERNiCr-3 filler is better than ER309L.