Structure and wear resistance of R6M5 steel based coatings

Features of the structure of R6M5 steel based coatings obtained by multiscan electron-beam fusion of a hardening composition in vacuum have been studied. It is established that the carbide subsystem of the hardened layer is characterized by a multimodal distribution of carbide particles with d₁ = 3.8 μm, d₂ = 0.65 μm, and d₃ < 0.25 μm. The volume fraction of M₆C secondary carbide and retained matrix austenite can be controlled within broad limits by varying thermal parameters of the electron-beam fusion. An increase in the retained austenite fraction in the coating leads to improved wear resistance due to the γ → α′ marten-site transformation during friction and the presence of dispersed secondary carbides inside the matrix grains.