Deposition Characteristics of Multitrack Overlayby Plasma Transferred Arc Welding on SS316Lwith Co-Cr Based Alloy-Influence ofProcess Parameters

Abstract

Plasma transferred arc welding (PTAW) is one of the outstanding overlay coating technique used in numerous industries including pressure vessel, automotive, chemical, nuclear, etc. owing to its superior characteristics, low dilution and high efficiency in the coating. In the present investigations, an effort is made to investigate the multitrack overlay deposition by PTAW on 16mm thick 316 L plate by CO-Cr alloy. Samples are produced under different processing conditions, as per full factorial central composite design of experiment with preheating of 200°C by maintaining the interpass temperature 250°C. Effects of transferred arc current, welding travel speed, powder feed rate, welding oscillation speed and stand-off distance on weld bead shape parameters comprising of width of deposition and reinforcement are presented and discussed based on experimental observations and fitted model. Relationship between the input process parameters with deposition characteristics is also presented in the form of regression equation. Lower current (100-120 A), intermediate travel speed (120-140 mm/min), intermediate powder feed rate (12-14 gms/min), lower oscillating speed (450-550 mm/min) and lower stand-off distance (6-8 mm) would give better deposition characteristics with minimum distortion, less residual stresses, no surface defects with strong metallurgical bond.