Plasma hardening of medium carbon steels

Abstract

Abstract The structure, size and hardness of the zone of hardening of pre-annealed steels (30XHMA, 34XH1M, 35XH2Φ, 38XΓH, 40XHMA, 40XH2MA, 45) was studied after treatment with a plasma arc of direct polarity. It was shown that plasma hardening forms a thin layer of martensitic-austenitic structure with variable composition and hardness on the treated steel surface. The zone subjected to hardening was represented by marten site of different dispersion and ferrite veins. Between the quenching zone and the base metal there was a transition zone with a gradient structure of plate perlite and elements of perlite-ferrite base, the share of which was gradually increasing. The structural-phase structure of this zone provided a smooth transition of mechanical properties from the hardened layer to the base metal. Dependences for management of a structural condition, hardness and depth of a zone of hardening were determined.