Increase the corrosion-fatigue strength of long size cylindrical products as a result of hardening by combined tension and torsion

Research the one of the methods of long size cylindrical products hardening at which realization in pre-surface area of a product favorable compressing residual tension by consecutive elastic-plastic deformation at first by tension, and then, at fixing the longitudinal deformation received at tension, by torsion is carried out. Instead of the existing modes of hardening including single torsion of a product in tension condition, the new modes, consisting in reversive torsion of a product in tension condition, are offered. The new technological modes providing optimum distribution of residual normal tension on cross-section of a product at minimum values of residual tangent tension are developed. As a result of carried-out comparative corrosion and fatigue tests high efficiency of hardening is proved by combined tension and reversive torsion.