Surface Modification of High Carbon Steel by Autogenous Pulsed Tungsten Inert Gas Arcing

Abstract

Pulsed Tungsten Inert gas arcing (PTIGA) has been employed at various pulse parameters keeping the energy input constant for surface modification of high carbon steel (En-31) by controlled fusion. Analytical studies on thermal cycle and isotherm of fused surface have been carried out to predict microstructure of the fusion and heat affected zones. The analytical predictions have been verified by the experimental observations of modified surface characteristics. The ability of PTIGA process to control the energy input and its distribution Significantly influences the solidification behavior, nature of phase transformation and morphology of various phases in the matrix. It happens due to influence of arcing over the depth of fusion and cooling characteristics of matrix during solidification. Optimization of pulse parameters of the PTIGA process allows surface modification of En-31 steel plate with significantly improved hardness avoiding hot crackin.