SELECTION OF TEST SANDS FOR ABRASIVE WEAR OF HIGH-CHROMIUM CAST IRONS

Dry sand/rubber wheel tests are used for low-stress abrasive wear. Tes t sands have to be selected to simulate an actual abrasive. But, hardn ess, roundness and size of sands have usually been a major concern. Th e present paper, restricting to abrasive wear in coal pulverizing mil: , descries an experimental study on the selection of test sands based on similarity in abrasivity against white cast irons. Single-scratch t ests were performed using a rubber wheel tester. The width to depth ra tio of a groove, groove area and load on a single grain were measured or calculated for five kinds of martensitic white cast irons scratched by various sands. They were compared with those by hard particles ext racted from coal. Two commercially available sands were selected, havi ng similar abrasivity with larger and smaller sands extracted from coa l. The characteristics of grooves such as the groove area were correla ted with the wear rate in conventional sand/rubber wheel tests, Demons trating strong dependence of the wear resistance on the size of sands, it was concluded that both two selected sands have to be use for rubb er wheel wear tests as far as abrasive wear for coal pulverizing mill is concerned.