Effect of Heat Treatment on the Low-temperature Resistance of 42CrMo Steel in Electric Power Fittings

Abstract

The mechanical properties and low-temperature resistance of the 42CrMo steels utilized in electric power fittings after different heat treatments were comparatively investigated. Results indicated that a tempered sorbite with refined structure was obtained in the steels and the mechanical properties and low-temperature resistance were consequently improved after quenching + quenching + tempering and cyclic quenching and tempering, especially after the latter. The product of strength and elongation reached up to 25725 MPa% and the impact energy at -50 °C increased to 48 J after cyclic quenching and tempering as compared to 16562 MPa% and 19 J after conventional quenching and tempering. The 42CrMo steel after cyclic quenching and tempering can be considered as a suitable candidate for connection fittings in electric power transmission line.