Effect of rust on the steel surface and the method of adhesion

The surface morphology of steel and rust method used is closely related to its adhesion coating and tube sheets have a great impact. Rust using a wire brush, brush off the rust can tilt the scales and dirt, while the tube sheet adhered to a solid oxide brush can not afford. Use throw (spray) pill rust, not only thoroughly cleared away rust, scale and dirt, and the pipe surface at Mount Shot crashing and erosion, the formation of a uniform roughness. According to reports, throw (spray) pill form toothed anchor pattern, it can make a polished metal surface area is increased many times. This not only expands the physical adsorption tube surface area, but also greatly enhance the mechanical action of the coating and the pipe surface. Use throw (spray) pill rust, rust can improve the quality of steel surface morphology changes, expanding the surface area, greatly increasing the adhesion of the coating and the surface of the tube. Meanwhile, steel through throw (spray) rust after pill, tube table due to the violent impact and strengthen steel shot. Material strength increases by about 80%. Stress corrosion-resistant to nearly double. Surface hardness also have different degrees of increase, in addition, after the steel shot hit, but also to eliminate the internal stress of the weld, for hidden cracks and pipe table on the wall over corrosion, plays the role of a comprehensive inspection.

Steel shot blasting on surface roughness after, if too large, not only consume the paint, air may also be trapped in the tooth anchor pattern of “trough” harm the coating. It may also occur pierced coating of “spikes”, undermine the integrity of the coating, causing corrosion. As for the surface roughness to what is appropriate, some advocates 50μm or less, the British Standards shall not exceed 100μm, it was hoped at 75μm or less. Steel abrasive surface roughness depends on the proportion of the projectile, the size and speed of the three main factors, by adjusting these three factors, you can get different surface roughness.