Effect of welding conditions on microstructure and properties of type 316L stainless steel submerged arc cladding

Mathematical models were developed using response surface methodology for studying the direct and interaction effects of submerged arc welding parameters on stainless steel cladding geometry. The process parameters obtained from those models were employed to clad IS:2062 structural steel plate of 20-mm thickness using 316L stainless steel wire of 3.15-mm diameter. A low dilution of 22.57% was achieved in the cladding. Dilution was low when both voltage and welding speed were either high or low. Requirements of carbon and ferrite contents in the cladding were met by achieving low dilution in a single layer as well as multilayer cladding. Color metallographic techniques revealed that in the as-welded condition of cladding, the microstructural constituents of the HAZ, fusion boundary zone, and cladding surfaced with a low dilution condition were bainite and ferrite, martensite, and austenite plus ferrite, respectively. The hardness of the existing martensitic structures at the intermediate mixed zones in overlays was below 400 VHN, which was attributed to the lower carbon content in the cladding. The solidification modes were found to be austenitic, ferritic, and austenitic and ferritic. The microstructure was found to be mainly cellular or cellular dendritic. The measured ferrite contents of cladding were well within their corresponding predicted values. The cladding possessed good ductility and resistance to intergranular corrosion.