Research on Controlling the Distortion of Head Hardening Rail - CANCELLED

Abstract: Head hardening rail can greatly improve the service life of rail especially on heavy haul railway, but it is difficult to control the distortion of rail not only during the heat treating process but also when the rail is cooled to room temperature, because the rail is heated and cooled continuously only on rail head. In this paper we find a good way of controlling the distortion of rail based on long time experience. This method includes 4 steps, first induction preheating full profile of rail to a temperature little lower than austenitizing temperature, then induction heating the rail head locally to a temperature higher than austenitizing temperature, cooling first by compressed air to a temperature of completely finishing transformation of austenite to pearlite, and finally cooling the rail head with mist to control the distortion of rail. The experiment show that head hardened rail has good straightness when it finished heat treating and cooled to room temperature. With this method the rail with the length from 25 meter to continuously welded rail of 500 meter can successfully head hardened continuously with little distortion, and the heat treated rail show good mechanical properties of improved about 10HRC of hardness and 200MPa of strength on rail head and also improved toughness and plasticity, but the properties of section other than rail head is almost the same as hot rolled rail.