THERMAL PROCESSING OF RAIL HEAD WORKING SURFACE Russian patent published in 2015 - IPC E01B31/18 C21D9/04 C21D1/40 

FIELD: process engineering.

SUBSTANCE: invention relates to surface hardening by electric contact thermal processing. Proposed process comprises machining of rail head by mobile device directly at tracks without dismantling of rails. Machining is performed by electric contact heating with electric current passing through contact elements pressed against machined surface. Heating zone and rail head with critical surface wear of 1.5-2.0 mm and martensitic structure are, then, cooled. Rail head heating is performed to quenching temperature of 850°C and cooled by water with temperature of 18-20°C. Before thermal processing, rail head surface is corrected by finishing. Proposed device is composed of car on flanged wheels, its frame being made up of fixed and moving parts. Frame fixed part is provided with guide slides to displace frame moving part arranged perpendicular to frame moving part motion direction. Said frame moving part has sliding heating contact elements arranged on both sides, grinding heads with drive composed by brackets and telescopic bars, heating contact rollers and cooling device with jets. Note here that frame moving part is engaged with fixed part by two-way hydraulic cylinder with two-way rod. Heating elements and grinding heads are provided with regulators of force of pressing to rail head working side surface and connected with telescopic bars via isolating elements. Heating contact roller has current collector with cushion springs.

EFFECT: higher wear resistance and longer life of tracks.

7 cl, 1 tbl, 5 dwg