New composites based on aluminium alloy grinding waste for post-printing machines

Abstract

Post-printing equipment contains many antifriction parts made of cast aluminum alloys that work at sliding speeds up to 2.0 m/s and loads up to 3.0 MPa with liquid lubrication. Such parts often have unsatisfactory functional properties due to unstable lubricant supply to the contact area or other emergencies [1]. This leads to damage to the part, the unit, and the post- printing equipment as a whole. The use of grinding waste has become an alternative for creating new effective aluminium antifriction composites. The objective of the study is to determine the structure and properties of new antifriction composites based on grinding waste of aluminium alloy D16+(6.0‒8.0) wt.% MoS2. The initial D16 alloy grinding waste was subjected to regeneration: cleaning from abrasives and drying. D16 alloy powders were mixed with (6.0-8.0)wt.%MoS2, cold-pressed at 550 MPa, and followed by hot pressing at 300 MPa and 400°C to minimise porosity. The structure was studied using metallographic, scanning electron microscopes and X-ray spectroscopy [1]. The tribological tests were carried out on the VMT-1 friction machine at a speed of 1.0-2.0 m/s and friction pair loads of 2.0-3.0 MPa in pair with a 40Kh steel counterface (HRC 47-49). The microstructure is a metal matrix (Al α-solid solution) based on the D16 aluminium alloy regenerated grinding waste and uniformly distributed MoS2 solid lubricant. Antifriction tests showed the advantages of the new composite made from the D16 alloy waste over cast aluminium alloy D16. The friction coefficient of the new composite was 0.16-0.18, and wear intensity was 32-37 µm/km in tribological tests at 3.0 MPa and sliding speed of 2.0 m/s. While the cast alloy D16 at operation without lubrication had a friction coefficient of 0.38-0.39 and wear intensity of 75-80 µm/km. The developed technology provided a high level of functional properties and stable operation of the composite in self-lubrication mode.