Predicting breakage behavior and particle size of bronze and cast iron machining chips pulverized by jet milling

Abstract

It has been proposed that the breakage behavior of particulate materials can be described by two material parameters fmat and Wmin. fmat describes the resistance of the material to fracture in impact pulverization and Wmin characterizes the specific energy which a particle can absorb without fracture. It is shown in this study that this concept can be used to quantify breakage behavior of bronze and cast iron chips in jet milling process and also to predict particle size of the jet milled product. Different tin bronze and cast iron chips with varying initial size were pulverized in a target plate jet mill with different velocity. fmat was found to be in the range of 0.06–0.09 and 0.18–0.25 for bronze and cast iron alloys, respectively. For the cast iron alloys fmat increased with increasing content of carbon and silicon. Similarly, for the bronze alloys, fmat increased with increasing tin content. An equation was developed to predict mean particle size of the jet milled chips as a function of the kinetic energy, initial chip size and material parameters. The experimental results of various alloys confirmed that the mean particle size after single and multiple impacts were accurately predicted.