Continuous impact/abrasion testing: influence of testing parameters on wear behaviour

In many fields of industry, erosion is the dominant wear mechanism that reduces the lifetime of costly machine parts such as crushers, hammer bars, or cutting edges. Particles of specific mechanical and geometrical properties hit the surface with a certain energy and, under different angles of impact, cause abrasion and surface fatigue, or, in the case of high single particle impact energy, immediate damage by exceeding the rupture strength. Different types of wearfacing alloy layers applied through welding are used to protect exposed surfaces. The structure of state-of-the-art welding alloys is always based on multi-phase systems containing effective hard phases based mainly on borides and carbides of W Cr, Nb, and others. Within this work the so-called continuous impact abrasion test was established to compare different wearfacing alloys as described above and to develop a relation between parameters of the tribological system and properties of multi-phase materials. In the first step, morphology, energy, and size of the abrasive particles were varied and applied onto two different Fe-based wearfacing alloys. Observations on the phenomena of wear on the test samples accompanied by a quantitative evaluation of volumetric wear loss finally resulted in defining a model that enables a prognosis oriented consideration of wear. It was found within this study that wear phenomena in the microstructure have to be clearly differentiated according to the total energy applied and the impact energy of a single particle.