Importance of Surface pretreatment for anti-corrosion coating operationTAA technical department believes that surface pretreatment plays the most important role in the performance of the coating. Among many factors affecting the performance of coating, surface pretreatment is the most important one.
Surface pretreatment is a basic work
Surface pretreatment can create conditions for coatings with excellent performance in two aspects: in mechanical, it provides surface roughness for coatings; And in chemical, it makes the molecules of the coating in close contact with the surface of the steel substrate.
Overcome the adverse effect of smooth surface for coating
If the surface is smooth, there will be no good adhesion between the coating and the surface, and the coating on the surface can be removed effortlessly. On the contrary, if the surface of the workpiece is as rough as sandpaper, it is not easy to remove the coating.
After shot peening (sand blasting) treatment, the steel surface will be as rough as sandpaper, which is what we often call surface roughness.
Harmful substances invisible to the naked eye
During the surface treatment of rusted steel structure before painting, the parts showing corrosion pits after shot blasting (especially the bottom of corrosion pits) may contain soluble salts. Dry shot blasting cannot remove these salts. Therefore, before painting, it is best to check whether there are soluble salts and their concentration on the workpiece surface with a special field test instrument. If the concentration of soluble salts exceeds the allowable value, measures shall be taken to remove them.
Economy is a problem that we should consider when determining the surface cleaning level. Generally speaking, the higher the cleanliness requirements, the higher the cost of cleaning. For steel surface cleaning, the cleanliness requirements of the most thorough cleaning level (SA 3) are more expensive than those of the non thorough cleaning level (SA 2). The surface cleaning of steel structures used in severe corrosive environment needs to reach a high level, but in other occasions, the cost-effectiveness of coating service life is also an important factor in the selection of cleaning level.
The workpiece treated with non-metallic abrasive has no Fe atom residue and is not easy to rust and discolor, but it has high crushing rate, large dust and serious pollution, which does not meet the requirements of environmental protection.TAA stainless steel grit can well solve the problems encountered. In a specific cleaning field, the workpiece is required not only to be free from corrosion and discoloration after surface treatment, but also to form a certain roughness on the surface and achieve sufficient adhesion after coating.
The steel grit made of high carbon steel shot can meet the rough requirements after cleaning, but Fe atoms will remain on the surface, resulting in rust and discoloration and affecting the coating quality.
Stainless steel cut wire can prevent the workpiece surface from rusting and discoloration, but it will become round during blasting, so it can not meet the roughness requirements.
Stainless steel grit is a stainless material grit particle, it can not only solve the problem of corrosion and discoloration due to residual Fe atoms, but also make edges and corners to form the required anchor depth, improve the coating quality and meet the coating requirements. It has a broad market prospect.
In addition, stainless steel grit can replace a variety of mineral sand and non-metallic abrasives, such as alumina oxide, emery, quartz sand, glass beads, etc.
Compared with non-metallic abrasives, stainless steel grit can bring lower operation cost, greatly reduce dust emission, reduce dust removal cost and improve the working environment.
Application of stainless steel grit: