Surface treatment in which steel grit, sand, or other abrasive material is blown against an object to produce a roughened surface or to remove dirt, rust, and scale.

Abrasive-Blasting is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface, or remove surface contaminants. A pressurized fluid, typically air, or a centrifugal wheel is used to propel the media.

Common abrasives used include:

  • Steel shot
  • Steel grit
  • Glass bead
  • Crushed glass
  • Aluminum oxide
  • Silicon carbide
  • Plastic
  • Walnut shell
  • Corn cob
  • Baking soda
  • Ceramic grit
  • Copper slag

The table below gives a summary of the different qualities in surface preparations used by some standards.

Description Swedish SIS 05 5900 American SSPC-SP International ISO-8501-1
White metal Sa 3 SSPC – SP 5 Sa 3
Near white metal Sa 2½ SSPC – SP10 Sa 2½
Commercial blast Sa 2 SSPC – SP 6 Sa 2
Brush-off blast Sa 1 SSPC – SP 7 Sa 1
Power tool cleaning St 3 SSPC – SP 3 St 3
Hand tool cleaning St 3 SSPC – SP 2 St 2

Initial condition of steel as per ISO 8501-01.

Rust grade Pictorial example Description
A Steel covered completely with adherent mill scale and with, if any, little rust.
B Steel surface which has begun to rust and from which the mill scale has begun to flake.
C Steel surface on which the mill scale has rusted away or from which it can be scrapped, but with little pitting visible to the naked eye.
D Steel surface on which the mill scale has rusted away and on which cosiderable pitting is visible to the naked eye.

Pictorial examples of surface preparation according to ISO 8501-01

Cleaning standard Initial steel condition
A B C D
St2 – Hand tool cleaning Not applicable
St3 – Power tool cleaning Not applicable
Sa1 – Brush-off blast Not applicable
Sa2 – Commercial blast Not applicable
Sa2.5 – Near white metal
Sa3 – White metal