First: derusting grade. For the construction process of epoxy, ethylene, phenolic and other anti-corrosion coatings commonly used for alloy pipes, the general requirement is to reach the near white level on the surface of alloy pipes. It is proved by practice that almost all oxide skin can be removed with this derusting grade, and rust and other dirt can fully meet the adhesion requirements of anti-corrosion coating and alloy pipes, The spray derusting process can make the quality reach near white level stably and reliably at a low cost.
Second: if you want to achieve the ideal derusting effect, you need to select the abrasive according to the hardness of the alloy pipe surface, the original corrosion degree, the required surface roughness, coating type, etc. single-layer epoxy, two-layer or three-layer polyethylene coating. In order to achieve the ideal derusting effect, you need to use the mixed abrasive of steel sand and steel shot. Because the steel shot has the function of strengthening the steel surface, the steel sand has the function of etching the steel surface.
Third: in order to obtain better uniform cleanliness and roughness distribution, the design of abrasive particle size and ratio is very important, because too large roughness is easy to cause the anti-corrosion coating to become thinner at the peak of anchor pattern. At the same time, because the anchor pattern is too deep, it is easy to form bubbles in the anti-corrosion process, which seriously affects the performance of the anti-corrosion coating. (in actual operation, the ideal ratio of steel sand and steel shot in abrasive is difficult to achieve).
Fourth: before spray treatment, the grease and scale on the surface of the alloy pipe are removed. The pipe body can also be preheated to 40-60 ℃ with a heating furnace to keep the surface of the alloy pipe dry, because the surface of the alloy pipe does not contain grease and other dirt, which can enhance the effect of rust removal. In addition, the dry surface of the alloy pipe is also conducive to steel shot, The separation of steel sand from rust and oxide scale will make the surface of the alloy pipe more clean after rust removal.
