The behavior of welded dissimilar metals structures under rotating reversed cyclic bending

A cantilever type rotating bending testing machine was used to test several welded specimens, these consisted of welding of steel ST60 to stainless steel SS304, and welding of steel ST60 to stainless steel SS316, using different filler types of stainless steel SS308, SS309 and SS310. The effect on the heat affected zone (HAZ) was investigated. Fracture surface examinations were also carried out. The numerical analysis adopted the finite element package ABAQUS® to model the welded specimens. Elasto-plastic non-linear analysis was conducted for stress distribution contours. von Mises stresses were obtained as well as crack initiation fatigue life. Both numerical and experimental studies were carried out at four different levels of applied stress from 0.6Sy to 1.2Sy at steps of 0.2Sy. The developed maximum stresses exhibited linear behavior followed by non-linear behavior with further increase of applied stress. The filler type had a pronounced effect on the developed stress such that higher stresses were obtained for filler SS308 and lower stresses for SS309 and for SS310, respectively. The crack initiation fatigue life decreased non-linearly with increasing the applied stress and it was greatly affected by the type of filler material; filler SS310 had higher fatigue life cycles than SS309 while SS308 had the lowest fatigue life cycles. The crack initiation fatigue life (Ni) and failure life (Nf) exponentially decreased with the increase in the applied stress. The experimental and numerical results were in good agreement. The SS310 filler, which has the highest Cr%, Mn% and Ni% is the best filler for welding ST60 to SS304 and also for welding ST60 to SS304, and it is recommended for such welding applications.