Cleaning metals grit blasting

Grit blast to grade 2k of Swedish Standard SIS 055900 (20) to achieve a maximum peak-to-valley depth of at least 50 p.m, using a hard angular clean metal grit which is free of any grease contamination. 

Sprayed coatings These are of the greatest importance, particularly for the protection of structural steel or certain aluminium alloys. The metal to be coated must be grit blasted shortly before spraying to provide a clean rough surface. Chilled iron grit is used for most steelwork, while alumina or silicon... 

All metal surfaces such as mild steel should be grit blasted, normally to SA 2-5 as defined in Swedish Standard SIS 055900. If the surfaces are contaminated with oil, grease or a chemical from previously used items, the contamination is usually removed by sweating in steam prior to grit blasting. Concrete surfaces must be clean and dry and any laitence must be removed as it will affect the bond of the lining. Preferably the surface should be grit blasted. 

Pretreatment of the substrate for plasma spraying consists only of cleaning and mild grit-blasting. If the bulk substrate is not capable of withstanding the temperatures involved, it may be necessary to apply a film of a metal such as nickel or molybdenum to provide a stable substrate. Plasma spraying has not been widely used, and for many applications has probably been superseded by sputtering. 

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