Surface treatment method of space frame Steel pipe before painting

The painting of bolt ball space frame steel pipe has the function of anti-corrosion. Because the surface of steel bar will be covered with oxide skin, welding slag, dust and oil stain during processing, transportation and storage. So workers need to treat the surface of steel bar before painting to remove the rust,burrs and other substances on the surface, otherwise, it will affect the adhesion and corrosion resistance between the coating and the pipes,and it will also cause the steel bar to continue to corrode under the protection of the coating, make the coating peel off, affecting the mechanical properties and service life of pipes.

       The following is the surface treatment method of space frame pipe before painting：

1. Manual processing

There are mainly scrapers, wire brushes or grinding wheels etc. The rust and scale on the surface of steel bar can be removed manually, but the manual treatment has high labor intensity, low production efficiency and unclean cleaning.

2. Chemical treatment

It mainly uses the acidic or alkaline solution to cause a chemical reaction with the oxide and oil on the surface of the steel bar to dissolve it in the acidic or alkaline solution, so as to remove the rust,scale and oil on the surface of steel bar. Chemical treatment is suitable for sheet cleaning. If the time is not well controlled, even adding corrosion inhibitor will cause over corrosion of sheet, For complex structural parts and porous parts, after picking with acid solution, the residual acid immersed in the gap or hole is difficult to be completely removed, Improper treatment will become a hidden danger of corrosion of pipes in the future, Chemicals are volatile, high cost, difficult to discharge after treatment, and poor treatment will cause serious pollution to the environment.

3. Mechanical treatment

There are mainly shot blasting method and shot peening method of steel pipe. Shot blasting is a method that uses centrifugal force to accelerate the shot and shoot it to the steel bar for rusting cleaning. It has poor flexibility and is limited by the site. It is blind to clean the steel bar and it is easy to produce dead corners on the inner surface of it, Moreover, the equipment has complex structure, many vulnerable parts, especially blades and other parts,fast wear,many maintenance hours, high cost and large cost investment.