Patents

Abstract

In order to select high erosion resistant materials or to estimate erosion damage caused by solid particle impact in actual cases, it is very important to take the mechanical properties of a material into account. It is well known that material hardness is closely related to erosion damage to materials. Another mechanical property apart from material hardness should be investigated, since the material hardness is not necessarily an essential indicator for industrially useful materials. From the fact that material removal is caused by indentation processes, material hardness is clearly one of the predominant parameter. It is also proposed that a new mechanical property directly associated with erosion damage exists in the indentation phenomenon. In quasi-static indentation tests using a WC ball, load relaxation after the completion of the indentation was measured and characterized for aluminum, copper, carbon steel and stainless steel specimens. It was found that the degree of load relaxation depended upon the ability of plastic flow for soft materials and upon brittleness accompanied by intergranular cracks between composite phases for hard metallic materials. It was concluded that a predictive equation containing both material hardness and the load relaxation ratio could be related to estimate experimental erosion damage data for many types of materials under a variety of impact conditions.