Sand Blast Surfaces

Abstract

The figures presented in this section relate to a surface typical of those produced by the sand blasting process. The surface is generated by particles of approximately similar size impinging on the surface at random positions and orientations. The impact leads to high kinetic energy being imparted to the surface, causing localized heating and, in many cases, asperity melting. The force of impact also blasts particles of the surface away from the main body of the material. It is probable that the kinetic energy of each individual event is approximately constant. Thus a number of random events clustering in similar positions on the surface — a statistically likely occurrence — will lead to the formation of larger valleys of the kind that become evident in this surface when it is subjected to simulated wear. The result is a structure that is random, not only spatially but also in amplitude. Depending upon the size of the blasted particles and their velocity, the surface may be extremely rough, or, alternatively, less rough with a fine overall structure. Irrespective of the amplitude of the roughness encountered, the random nature of the surface would be similar throughout all types of surface generation conditions.