An investigation on weld quality characteristics of pulsed current micro plasma arc welded austenitic stainless steels

Abstract

Micro Plasma Arc Welding (MPAW) is one of the important arc welding process commonly used in sheet metal industry for manufacturing metal bellows, metal diaphragms etc. The present work discusses about the weld quality characteristics of various austenitic stainless steels namely AISI 304L, AISI 316L, AISI 316Ti, AISI 321 which are commonly used for manufacturing of metal bellows. Square butt joint is used in the welding and no filler wire is used. Welding is carried out at fixed values of input parameters and same thickness of 0.25mm for all the steels. Peak current, background current, pulse rate and pulse width are considered as the main welding process parameters of MPAW process, where as weld bead geometry, microstructure, grain size, hardness and tensile properties are considered as weld quality  characteristics. Results reveal that out of all the materials considered in the study AISI 304L attains better weld quality characteristics for same welding conditions.

Keywords: Pulsed current micro plasma arc welding, microstructure, grain size, hardness, tensile properties.