Effect of autogenous arc welding processes on fatigue crack growth behaviour of ferritic stainless steel joints

Abstract

The present investigation is aimed at to study the effect of autogenous arc welding processes on fatigue crack growth of the ferritic stainless steel conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile, impact and fatigue properties, micro hardness, microstructure and fracture surface morphology of the continuous current gas tungsten arc welded, pulsed current gas tungsten arc welded and plasma arc welded joints were evaluated and the results are compared. From this investigation, it is found that plasma arc welded joints of ferritic stainless steel showed superior fatigue performance compared with continuous current gas tungsten arc welded and pulsed current gas tungsten arc welded joints and this is mainly due to the superior mechanical properties, preferred microstructures in the fusion zone region and favourable residual stress field in the fusion zone region. © 2008 ISIJ.