Increasing of carbon steel durability by surface hardening

Abstract

Conditions of machine elements during exploitation, also durability and security of all construction depends a lot on the state of metals surface layer. Hardening of metals surface allows to change expensive metals to cheap ones. Improvement of surface quality allows to increase the durability of all construction. In this work the influence of various kinds of surface treatments (hardening with high frequency electric current, rolling by rollers, tempering) on fatigue strength of carbon steel specimens were investigated. Analysed technology of surface hardening greatly increases the fatigue strength and durability of specimens. It was estimated that hardening effect depends on the residual stresses introduced applying deformation and thermal treatment regimes. The optimal treatment of the analysed carbon steel is deformation up to 1 mm depth, hardening with high-frequency electric current and tempering for 2 hours at 200 °C.