Plasma hardening of heavily loaded parts of soil-cutting machines

Abstract

The influence of plasma hardening on hardening processes of heavy-duty and, therefore, wear parts of working elements of soil-cutting machines has been studied. It is shown that surface plasma hardening of ploughshare made of structural steel 65Mn in the hardened zone with thickness of 0,8 mm leads to formation of gradient-layered (mixed) structure consisting of finely dispersed mixture decay products of fine-grained austenite with variable microhardness in the range of 760 – 395 HV. It is confirmed that the creation of gradient-layered structure and features of its formation after the surface plasma treatment are explained by ultrahigh heating and cooling rates, unattainable with traditional methods of heat treatment.

Keywords

• structural steel
• 65Mn
• plasma hardening
• heavy-loaded parts
• gradient-layer structure
• microhardness