Analysis of reciprocating hammer type impact wear apparatus

Abstract

Repetitive impact wear of metals is caused by primary wear mechanisms removing material from the surfaces and is responsible either solely, or in part, for the failure of engineering components (e.g. automotive valvetrains, wheel-rail contacts, mining equipment). Fundamental work exists, but overwhelmingly considers the impact wear of a particular material or surface treatment.The mechanisms involved are variously oxidative, adhesion, abrasion, surface fatigue and plastic deformation. The dominance is controlled by stress, sliding conditions, impact energy, and the difference in material properties, particularly those of plastic deformation, between the two surfaces. There is a paucity of published work that solely investigates and characterises the fundamentals of impact wear.Impact wear test apparatus falls into two groups; projectiles propelled into a stationary target/specimen, or a target/specimen being repeatedly struck by a hammer. The former type is similar to that commonly used for erosive wear, so the reciprocating hammer/striker type design, was chosen for analysis here.Analysis was performed on specimens with impact wear scars that feature both material displacement and material loss, enabling comparison between different measurement techniques to be made. This provides a protocol for easier comparison of data, promoting improved models, and furthers the understanding of the apparatus’ performance.