Tribotechnical Properties of Composite Materials Produced from ShKh15SG Steel Grinding Waste

Abstract

The structure and antifriction properties acquired by a new composite produced from ShKh15SG structural steel grinding waste with additions of CaF2 solid lubricant are examined. The material is intended to operate at 300–400°C under loads of 5.0–7.0 MPa in air. Analysis of the secondary structures and antifriction properties shows that contact surfaces of the test material and counterface are covered with continuous antiseize friction films in the operating conditions in question. They contain chemical elements of both the composite and the counterface, as well as calcium fluoride. Oxygen is also present in the friction films as it participates in their development, entering into chemical reactions with the contacting elements to form various oxides and promote oxidative wear. The antifriction ShKh15SG + 5.0–7.0% CaF2 composite can be effectively used in friction units intended to operate in self-lubrication conditions at 300–400°C under loads of 5.0–7.0 MPa in air. In these operating conditions, the wear rate of the self-lubricating films that form on friction surfaces is balanced by their recovery rate. This is confirmed by high tribological properties. Recovered industrial grinding waste of structural steels is shown to be promising as a metal matrix to make high-quality antifriction composites for specific operating conditions. The structure and properties of the composites can be controlled by choosing the chemical composition of grinding waste and applying optimized manufacturing modes.