Microstructure and mechanical property of cast iron spray-welding

In order to avoid chill and quenched structure,spheroidal graphite iron was spray-welded using oxyacetylene spray torch with selffluxing alloy powder F101 and Ni60.It was also welded using arc welding with cast iron electrode Z308.The tensile strength,hardness and metallurgical structure of samples were inspected.The results indicate that chill,quenched structure and crack were appeared in the welds of arc cold welding.The hardness of fusion zone of using Ni60 alloy powder increased up to 701 HV,and it is badly harder than that of base metal.The hardness of heat-affected zone and weld using F101 alloy powder is almost the same as that of base metal.Metallurgical structures indicate that there exists metallurgical bonding besides mechanical bond,and there arenot any cracks in the weld and the bonding strength is higher than that of arc welding with cast iron electrode.