Surface treatment of steel structure

Now for the surface treatment of steel structures, it is not only rust removal work such as sanding and sandblasting, and surface cleaning work such as oil removal and dust removal. Surface treatment inconsistent with the paint will hinder the further improvement of the coating work quality, and the performance of the paint will not be better. There are many contents for surface treatment. The following introduces the factors that have an important influence on the performance and quality of the coating.

1. Oxide scale: The oxide scale is formed by the reaction of a hot steel plate with external oxygen during the production process. Therefore, the surface of newly produced hot-rolled steel is generally covered by blue-black oxide scale deposits.

2. Salt: Soluble corrosion products will be hidden under layers of iron oxide, usually iron chloride and ferrous sulfate. Because they are water-soluble, they will cause osmotic pressure blistering of the coating in the future.

3. Corrosion products: rust is a loose substance that often traps moisture and oxygen. The corrosion products that are formed long ago often contain soluble salts. Soluble salts not only directly damage the coating, but also cause problems such as osmotic pressure, blistering, and poor adhesion. It is also a catalyst that will increase corrosion.

4. Oil stains: Most paints have a repulsive force with oil stains, which is greater than the attractive force of grease. Grease on the substrate will cause shrinkage and poor adhesion.

5. Dust: Dust on the surface of the steel will affect adhesion problems, and the presence of dust will cause blistering problems after the coating is immersed in water.

6. Electric welding seam: The deposits of welding fumes and slag left on both sides of the welding seam are water-soluble, which will cause osmotic pressure and blistering.