Residual stress relief in cold-extruded rod

Abstract

The residual stresses in cold-extruded mild-steel rods have been estimated by the longitudinal slitting method, and the effect of low-temperature annealing on the residual stress level has been investigated. For the extrusion ratios used (2.78:1 and 4:1), residual stress relief appears first at about 250°C and is substantially complete at about 500°C, the tensile strength having decreased over this temperature range by less than 10%. A correction factor is proposed that allows the determination of residual stresses by the longitudinal slitting method to be independent of slit length.