Surface modification of duplex stainless steel with SiC preplacement using TIG torch cladding

Surface modification of duplex stainless steel is important to make this material suitable for tribological and high temperature applications. The surface modification using fine SiC (20μm) powder preplacement by TIG torch technique has been performed on the surface of duplex stainless steel. The TIG torch was employed with varying operating welding variables such as welding current of 80 A, 90 A and 100 A and energy input of 648, 768 and 1440J/mm. The composite surface layer was characterized using Vickers micro-hardness tester and scanning electron microscopy (SEM). Based on the experimental results, it was found that re-solidified composite layer produced maximum hardness of 833.6 Hv0.5kgf from substrate hardness of 250 Hv0.5kgf for TIG processed of 768J/mm energy input. The microstructure revealed the formation of dendrite phase due to complete melting of SiC in the modified layer. The formation of dendrite contributes to the increase of hardness of this material.