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There are two kinds of representative international standards of blasting equipment for cleanliness: one is the "SSPC-" formulated by the United States in 1985; the second is the "Sa-" formulated by Sweden in 1976, and it is divided into four levels: Sa1, Sa2, and Sa2 .5, Sa3, is the international common standard.
Sa2.5, the table's blast cleaning level, that is, cleanliness, is very thorough blasting or blasting. The surface of the steel should be free of visible grease, dirt, scale, rust and paint layers and other attachments. Any remaining traces should be only slight stains of dots or stripes.
Technical standards for treatment: the surface of the workpiece should be free of greasy, dirt, scale, rust, paint, oxide, corrosion, and other foreign substances (except for defects), the defects are limited to not more than 5% per square meter of the surface, May include slight shadows; slight discoloration due to defects and rust; oxide scale and paint defects.
There are also the following standards:
Sa1-Light spray or projective rust removal, the steel surface should be free of visible grease and dirt, and there should be no adherence such as loose oxide scale, rust and oil bare coating
Sa2-Thoroughly spray or project to remove rust
There will be no visible grease and dirt on the surface of the steel, and it will oxidize. The attachments such as rust and paint coating have been basically removed, and the residues should be firmly attached
Sa3-Spray or projective rust removal to make the steel appear clean There are two levels of rust removal for steel surfaces that have been rusted by hand and power tools
St2-Thorough derusting of hand and power tools, the surface of the steel should be free of visible grease and dirt, and there should be no loosely adhered oxidation, rust, paint coating and other attachments
St3-Very thorough derusting of hand and power tools, the steel surface is free of visible grease and dirt, and there are no attachments such as loose oxide scale, rust, and paint coating.