Effect of Specimen Size on Tensile Strength of Welded Joint in Maraging Steels

Abstract

The influence of specimen size on the tensile strength of electron beam welded joint has been studied for four maraging steels. The strength was measured using specimens different in the plate width (W) and thickness (t) and the width (H) of the weld metal. The influences have been discussed on the basis of the plastic constraint of the base metal having higher strength than the weld metal.
The strength of welded joint rises gradually and reaches a constant value as W increases when t and H are both constant. This constant value of strength corresponds to the strength of infinitely wide welded joint. The minimum width (W_∞) at which the constant value is achieved is determined. When W and t are constant, the strength of welded joint of the width W_∞ increased with the decrease in H. When W andH are constant, it increases with the increase in t. The strength of welded joint increases with the decrease in the relative thickness (H/t) as the degree of the constraint from the base metal of the deformation of the weld metal increases. The width W_∞ is roughly given by W=5t in case (H/t) ≤1 and W=5H in case (H/t)>1. Similar results have been reported for high tension steels.