ANTIFRICTION COMPOSITE MATERIAL BASED ON TOOL STEEL GRINDING WASTE FOR PARTS OF PRINTING MACHINES

Abstract

The article studies the effect of the technological parameters for the manufacture of new effective antifriction composite materials based on7HG2VMF tool steel grinding waste with CaF₂ additions as a solid lubricant, on the structure, mechanical and tribological properties at the high friction speeds (bearings perform at the rotational speeds of 700 rpm and pressure up to 5.0 MPa in air). The paper illustrates the mechanism of new materials’ structure formation and its effect for properties after use the developed technological modes. Such technology is able to ensure the microheterogeneous fine-grained structure. The composite's structure consists of the matrix based on tool steel waste and uniformly distributed solid lubricant CaF₂. The metal matrix is perlite and consists of α-solid solution based on iron with hard grains of alloying elements’ carbides. Such heterogeneous structure promotes the high level of the antifriction properties at severe operating conditions. It was shown the behavior of CaF₂ in the friction area under high temperature operating conditions. The solid lubricant CaF₂ is evenly distributed over the entire friction surfaces. Calcium fluoride and chemical elements of the contact pair form an antifriction film, which provides self-lubricating conditions. It was demonstrated the possibility of predicting and controlling the behavior of antifriction materials at high rotational speeds by selection of initial metal grinding waste for ensuring the functional properties high level. The use of grinding waste to produce the effective antifriction materials makes it possible to partially solve the global problem of environmental protection.