Chiang Mai Journal of Science

     The current study focuses on the use the gas tungsten arc welding (GTAW) with nickel-molybdenum (Ni-Mo) coated filler materials to weld 304L and 202L stainless steel (SS) joints. The improvement of welding strength heavily depends on the characteristics of the filler metal. The GTAW filler materials are coated with Ni and Mo to facilitate the welding process. The results of the filler metals Ni Mo-304, Ni Mo-202, Ni Mo-316, Ni Mo-308 are contrasted with the normal-304 and normal-202 filler metal. The surface structure of weldment produced by Ni and Mo 308 coated filler metal shows uniform distribution of filler material. Also, significant improvement is noted in tensile strength and Ni-Mo coated 316 has more % of elongation than other filler metals. The impact toughness of Ni-Mo 308 is 98 J which is 76 % higher than normal uncoated 304 filler metal. The average micro hardness of the Ni Mo -308 show improvement about 12 % than normal 304. Furthermore, Scanning electron microscope (SEM) images are taken over the weldment to analyse the heat affected zone (HAZ) of Ni and Mo combination weldment structures.