Structure and Tribological Properties of Wear-Resistant Composites Produced From Brass Waste for Screen Printing Machine Parts

Abstract

The effect of the fabrication process on the structure and tribological properties of a new antifriction composite produced from grinding waste of brass L63 with CaF₂ solid lubricant was studied. The material is intended to operate under loads up to 3.0 MPa and sliding speeds up to 2.0 m/sec in friction assemblies of screen printing machines. The fabrication process ensured the formation of a two-phase antifriction composite structure: a metallic α-brass matrix with uniformly distributed CaF₂ solid lubricant particles. Comparative tests of the new composite produced from brass L63 grinding waste with (6.0–9.0)% CaF₂ demonstrated its advantageous antifriction properties over cast brass L63. The latter corresponds to CuZn37/CW508L (EN standard) or C27200 (ASTM standard, USA) brasses, which are conventionally used in the friction assemblies of Sakurai MS-80AII, Sakurai MS-80/102SD, and Sakurai SC-72AII/102AII/112AII/142AII screen printing machines. The composite from regenerated brass L63 grinding waste containing CaF₂ solid lubricant forms an antiseizure protective film on the contact surfaces at sliding speeds up to 2.0 m/sec and loads up to 3.0 MPa through the mass transfer mechanism. The film uniformly covers the surfaces. It is smooth and continuous, and its wear and regeneration rates balance under defined speed–load conditions. This minimizes friction, resulting in the lowest friction coefficient and wear rate compared to cast brass. Analysis of the functional properties allows the antifriction composite produced from industrial grinding waste of brass L63 with CaF₂ solid lubricant admixtures to be recommended for parts of screen printing equipment assemblies operating at sliding speeds up to 2.0 m/sec and loads up to 3.0 MPa.