Application of the contour method to determine axial residual stresses in cold extruded steel rods

Abstract

Residual stresses in cold extruded parts play an important role in both component lifetime and succeeding in manufacturing performance. When a cold extruded part is used directly, the lifetime of the part depends on the residual stresses induced during cold extrusion. On the other hand, if the part is exposed to post operations such as machining, residual stresses may cause distortions. Despite their importance, there are only a few residual stress measurement methods to assess axial residual stresses in full cylindrical thick components of massive forming. As high-energy X-ray and neutron diffraction methods are less available and considerably expensive, the contour method may be an alternative providing the accurate assessment of residual stresses without requiring specialized facilities. In the present work, residual stresses in cold extruded rods are determined via the contour method for various extrusion ratios. The finite element analyses for the same conditions are also carried out to provide the comparison to the contour method. The results indicate that the contour method can be a valuable candidate for the measurement of axial residual stresses in cold extruded thick components.