Papers by Keyword: Wear Mode

Abstract: This study aims to reveal the underlying mechanism associated with the enhancement of wear resistance of tool steels by deep cryogenic treatment and to resolve the issue of reported varied degree of improvement in wear resistance through structure-property correlation of cryotreated vis-à-vis conventionally treated AISI D2 steel. Microstructures of heat treated specimens have been characterized employing various techniques with specific emphasis on quantitative estimation of the characteristics of secondary carbides. Evaluations of properties include measurements of bulk hardness, apparent strength of the matrix, fracture toughness and dry sliding wear resistance under wide rage of normal loads supplemented by in-depth characterizations of worn surfaces, wear debris and subsurfaces of worn specimens in order to identify the operative mode and mechanism of wear. It has been demonstrated that the favorable modifications of the precipitation behavior of secondary carbides in addition to removal of retained austenite are the governing mechanisms for the enhancement of wear resistance of tool steels by deep cryogenic treatment. The cause of the reported varied degree of improvement in wear resistance by deep cryogenic treatment has been explained by disparity of the operative modes and mechanisms of wear.

Abstract: To understand the mechanism involved in the lapping process of the silicon nitride balls, the wear mode is investigated in this paper. The abrasion tests were performed on a ball-plate wear test apparatus with different loads (0~2N/ball) and slurry concentrations (5%wt~30%wt W20 B4C3). The abraded surface is observed by optical telescope. A wear-mode map, which defines the regimes for two-body abrasion or three-body abrasion dominating in the micro-scale abrasion test, is plotted with two axes: load and concentration of abrasive. An empirical formula for the wear mode transition is adopted to calculate the transition point S*, which can then used to predict the wear mode in lapping process of silicon nitride ball.

Abstract: In contact conditions of crane sheave steel materials against a wire rope, the contact surface of the sheave generally exhibits scuff damage. In the present study, sliding wear tests using annealed-low carbon cast steel were carried out under three kinds of normal loads calculated from the actual model conditions in a pin-on-disk grease lubrication test. The sliding speed was fixed at 220mm/s. Therefore, the wear behavior and wear mechanism and the residual stress distribution of the substrate surface were examined. The results of this study indicate that the wear rate of annealedlow carbon cast steel depends on the diameter of the wires. The wear mechanism of annealed-low carbon cast steel is characterized by fatigue and abrasive wear, but the wire shows partial adhesion due to micro abrasive wear by fatigue crack propagation. The contact distribution of residual stress is independent of sliding distance. Therefore, there are constant values on the contact surface.