Optimum conditions for blast cleaning of steel plate 1

Abstract

Technological investigations are described in which a laboratory set-up simulates conditions of practice when blast cleaning steel plate as well as possible.

The rate of cleaning is found to increase when more abrasive per unit of time is discharged. This means that high pressure, a large nozzle and a wide valve for metering the abrasive flow are advantageous, bur the actual setting of these variables should be mutually adjusted. The optimum blasting angle for removing millscale is about 45°, and the optimum nozzle to work distance 55–75 cm. The smaller the abrasive grains, the quicker the cleaning process. Air consumption decreases as, under otherwise constant conditions, the abrasive transport is increased. High cleaning rates are advantageous, because they lead to lower costs per m² for labour and power, whilst costs for abrasive hardly go up.