Observations on the use of hard-metal castings in the shot-blasting industry

Abstract

The rapid wear associated with the shot-blasting process — particularly in equipment using the mechanical method of abrasive propulsion via an impellor wheel — necessitates careful attention to the quality and materials used for the manufacture of wearing parts. Two categories of components are identified — those in direct contact with the abrasive such as the wheel parts, and those in indirect contact and associated with abrasive re-circulation. The metallurgical characteristics of high-chromium cast irons are discussed and the microstructural features in particular are shown to be of significance with regard to the suitability of these alloys for the manufacture of both categories of castings. The importance of various aspects of quality of these parts is stressed with optimum performance and minimum maintenance costs as an objective. An indication of the extent of quality control required during the manufacturing process to achieve these ends is outlined.