EFFECT OF POST WELD HEAT TREATMENT ON WELDABILITY OF CAST IRON USING NICKEL BASED FILLER MATERIAL

Abstract

The weldability of cast iron is considered very difficult because of excess carbon, lower ductility, high content of sulphar and phosphorus and effect of weld thermal cycle on the metallurgical structure of the cast iron. The experimental study is carried out for the analysis of effect of post weld heat treatment on weldability of cast iron using nickel based filler material. Microstructures of different zones of interest like weld metal; HAZ and base metal under two different welding conditions like simple welding and welding with post weld heat treatment were viewed and captured with an optical microscope coupled with an image analyzing software. The hardness of different zones of the weldments were measured using Rockwell hardness testing machine on (C) scale. Tensile strength and toughness of welded specimen were also determined to assess the change in ductility of the material in different conditions. Metallurgical investigations determine the variation of hardness across the different zone of the welded work piece like weld metal zone, heat affected zone and the base metal.