According to China National Standard GB8923-88 before coating steel surface modification grade and rust level, Shot Blasting Machine rust level is divided into four grades, with the letter "Sa" signaling.
Sa1: Mild jet or throwing rust. Steel surface has no visible grease or dirt, no adhesion strong oxide, rust and paint coating and other attachments.
Sa2: Thoroughly spray or throw out rust. Steel surface should have no visible grease and dirt, oxide, rust and other attachments have been basically removed, the residue should be firmly attached. Steel surface evenly is arranged after the formation of Cast Steel Shot, its anti-slip coefficient is of 0.35to0.45.