Welding Distortion of Austenitic Stainless Clad Steel

Abstract

The present paper gives a survey on shrinkage and distortion of groove welds of an explosive austentic stainless clad steel plate, paying attention to the effect of the clad metal of stainless steel with considerably different thermal and mechanical properties from those of the base metal of mild steel. The welding is performed by depositing a multi-pass bead in the groove of mild steel side by covered arc or submerged arc welding and subsequent back run of two passs with stainless steel covered electrodes. The interesting facts revealed are as follows:
1) The thermal cycles observed separately in clad and base metals at the same distance from the weld line are not so different during any pass welding as estimated approximately from the thermal conductivity of the two metals.
2) The formation of shrinkage and distortion of welds is, for the most part, due to the welding process of mild steel, and the effect of the back run is small.
3) By the submerged arc welding in mild steel groove, fan-like distortion of halves of weld on either side of weld line occurs so widely that the transverse shrinkage takes place in an arched curve along the weld line and the longitudinal shrinkage dose in a chevron in the transverse direction just as expansion occurs in the weld zone.
4) The angular distortion makes a general profile of welds saddle-backed with the stainless steel face concave along the weld line and convex in the transverse direction.
5) In the final state of welds, both the longitudinal remaining plastic contraction of weld zone and the longitudinal elastic strain corresponding to the residual stress distribute in conventional forms.