Influence of residual stresses in the tensile test of cold drawn wires

The aim of this paper is to investigate the influence of residual stresses, due to cold-drawing, on the shape of the tensile stress-strain curve and particularly its influence on the ratio sigma(0.2)/sigma(max) through a numerical and experimental work. It was found that residual stresses favours the onset of yielding and the ratio sigma(0.2)/sigma(max) decreases with increasing values of residual stresses. Because of the deleterious effect of residual stresses on fatigue and stress corrosion and because such stresses affect the ratio sigma(0.2)/sigma(max), it is reasonable to put a lower limit to sigma(0.2)/sigma(max) in the standards. The ratio sigma(0.2)/sigma(max) can be increased by relieving residual stresses, a common procedure after drawing. This fact is also ascertained.