Titanium based carbonitride alloy with wear resistant surface layer

摘要

A sintered body of titanium based carbonitride alloy according to the invention comprises carbonitride hard constituents in 5-25 % binder phase where the hard constituents contain, in addition to Ti, one or more of the metals Zr, Hf, V, Nb, Ta, Cr, Mo and/or W and the binder phase is based on cobalt and/or nickel. The sintered body has at least one outer surface with a <50 mu m thick surface layer, A, of a titaniumrich cubic carbonitride. Below this layer there is a <100 mu m thick binder phase enrichment, B, in which the binder phase content has a maximum of >1.2 of that in the inner of the body, D. Under the binder phase enrichment there is a <250 mu m thick binder phase depleted zone, C. The binder phase content in this zone has a lowest level <0.9 of the binder phase content in the inner of the body, D. Sintered bodies according to the invention are manufactured by heat treatment in an atmosphere of N2 and/or NH3 possibly in combination with at least one of CH4, CO and CO2 at 1100 - 1350 DEG C for 1-25 hours at atmospheric pressure or higher.