Estudo do tratamento de revenido por indução em camadas martensíticas produzidas em aço para trilho ferroviário

Abstract

Rail transport have as characteristic a high operational complexity. To preserve and maintain railways, engineering teams faces countless challenges. Among them is the formation of White Etching Layers (WEL), a thin, hard and brittle martensitic layer on the surface of rails,that potentiates fatigue-related defects. The WEL phenomenom has the grinding process as one of its origins, which is a maintenance process intended to recover tracks shape after their wear. As it is related to martensitic transformation, the tempering procces, to be applied after grinding, appears as a possible technological solution to revert the scenario of hardned layers on tracks. To investigate this option, a rail class TR-68 was submitted to induction hardening to obtain martensitic layers to simulate WEL and then induction tempering was applied to the previously formed martensite. Results shown succesful outcomes in forming martensitic layers, similar to WEL, but much thicker than the ones formed in grinding. Induction tempering showned effective to reduce hardness and to promote microstructural changes and hardness decrease.