Sandblasting is a commonly used method of rust removal. Its basic principle is to spray sand onto the surface of stainless steel strips with compressed air or high-pressure water, and use high-speed sand flow to remove rust and scale on the surface of stainless steel strips by impact and friction. And other dirt. There are two types of sandblasting: dry sandblasting and wet sandblasting. The abrasives used for dry sandblasting include quartz sand, steel sand, alumina, silicon carbide, etc. The commonly used is quartz sand, which should be dried before use. The compressed air injection at 700kPa pressure can remove the oxide scale and rust on the metal surface, make the roughness uniform, and increase the contact surface. Because the sandblasting operation will generate household heavy dust, it is harmful to human health. Dry sandblasting is mostly manual operation, which is suitable for various large, medium and small stainless steel strips with complex shapes.
Continuously automate the operation process of sand adding, sand blasting, sand collection, recycling, etc., so that the sand flow can circulate and flow continuously in a closed system, so as to completely avoid dust flying. This is the dust-free sand blasting method. In order to improve working conditions and avoid dust flying, wet sand blasting can also be used. Wet sand blasting means that the ratio of water to quartz sand is 1:2, and it is sprayed with compressed air at a pressure of 400 to 700 kPa. In order to prevent the sandblasting from being repeated If rust occurs, a small amount of chemical passivator, such as sodium nitrite, trisodium phosphate, sodium carbonate, soapy water, etc., can be added to the water in advance to keep the metal surface from rusting in a short time. The method of sand blasting and rust removal has the advantages of high rust removal efficiency, simple operation, more thorough rust removal, suitable surface roughness, and good adhesion of the coating film after painting, but the appearance is more complicated or the stainless steel strip on the inner surface needs to be cleaned , Stainless steel strips formed by thin plates are not suitable, and there are defects such as large sand consumption, excessive dust, and endangering the health of workers.