THE APPLICATION OF WASTE SILICA CYCLONE POWDER FOR THE PROTECTIVE COATING OF STEEL BILLETS

摘要

The role of a protective coating is to diminish the steel surface scaling during the reheating for hot rolling. The protective coating consists of several components, and the effect of the coating is based on the formation of the modification of Al_2O_3, amorphous SiO_2 and FeOxAl_2O_3, which all exhibit low permeability to oxygen at temperature up to 1200 deg C. The silica sand powder from the cyclone is a waste product in the separation of silica sand. Tests confirmed that waste cyclone powder could replace the silica flour as one of the ingredients in the protective coating. The results of the efficiency of the protective coating after the advanced application of waste cyclone powder on AISI 1059 and AISI 6150 steels are presented. The application of the coating decreased the oxidation and decarburisation of the steel surface during the reheating for hot rolling.