The influence of strain hardening on steel erosion wear studied by analytical modelling of impeller testing

Abstract

ABSTRACTAbrasive wear of steel is a common problem in the mining industry. It was tackled by many researches using analytical and numerical approaches. Despite the advantages of the analytical models to provide quick and elegant solutions, they were derived using several assumptions limiting their applicability, such as e.g. rigid-plastic flow. However, the consideration of strain hardening during impact is crucial to depict a real behaviour of tool material, which changes its mechanical properties during collision. In this research, a new analytical model is invented describing the impact of steel plate with a solid rock, while the material of the steel plate is hardening during penetration and scratching. The model provides a frame of analytical equations based on the second Newton law and equations of motion in vertical and horizontal directions. The motion in vertical direction is considered as an indentation problem and the motion in the horizontal direction as a scratch problem. This model incorporates the most general Holloman representation of strain-hardening law to capture the relationship between microstructural characteristics of steels and wear resistance. It was shown that the indentation depth, the pile-up height, length of the scratch and erosion ratio directly dependant on the strain-hardening parameters in Holloman equation. The model predicts the maximum indentation depth and scratch length as a function of strength coefficient and strain hardening exponent, but also of impact angle, mass of the rock, position of impact at the surface of steel plate and coefficient of friction during metal movement. The model was tested qualitatively by comparison with impeller-tumbler experiments using different steel plates. The solution obtained from this model could be used for quick and easy evaluation of the steel for mining tools in an industrial environment.