Enhancement of Microstructural and Mechanical Properties by Pulse Mode of Metal Transfer in Welded Modified Ferritic Stainless Steel

Abstract

The present study describes the enhancement of microstructural and mechanical properties by pulse mode of metal transfer in welded modified ferritic stainless steel (409 M) sheets (as received) of 4 mm thickness. The welded joints were prepared by varying modes of metal transfer at different heat input conditions (i.e. pulse mode at 0.5 kJ/mm and 0.9 kJ/mm and spray mode at 0.5 kJ/mm), using austenitic filler wire (i.e. 308 L) under Ar + 10% CO₂ atmosphere. It has been observed that the pulse mode of metal transfer significantly alters the weld metal composition compare to spray mode which promotes comparatively stable austenite in the welds and also depicts significant enhancement in grain structure even with the higher heat input condition. Present study clearly shows that pulse mode enhances micro-hardness of welded joints and toughness values of weld metals compare to spray mode of metal transfer for a particular heat input.