How to remove rust from welded steel pipe

　　1.rust removal grade, for the construction technology of epoxy, ethylene, phenolic and other anticorrosive coatings commonly used for welded steel pipe, the general requirement is to make the surface of the steel pipe close to the white grade. It is proved by practice that the rust grade can be removed almost all the oxide skin, rust and other dirt are fully satisfied. The adhesion requirements of the anticorrosive coating and API 5L Gr. B X46 Welded Steel Pipe, and the spray rust removal process can stabilize the quality to a near white level at lower cost.

　　2. to achieve the desired effect of rust removal, it is necessary to use the mixture of steel grit and steel shot according to the hardness of the welded steel pipe surface, the original corrosion degree, the required surface roughness, the coating type and so on to choose the abrasive, the single layer epoxy, the two layer or the three layer polyethylene coating. Abrasive materials. Because the steel shot has the effect of strengthening the steel surface, the steel grit has the function of etching the steel surface.

　　3.To obtain better uniform cleanliness and the distribution of roughness, the design of the particle size and proportion of the abrasive is very important. Because the roughness is too large to cause the anticorrosion layer to be thinner at the anchor point, and because the anchor line is too deep, it is easy to form bubbles in the process of anticorrosion, which seriously affects the anticorrosion layer.

　　4. Before the spray treatment, remove the oil and dirt on the surface of the welded steel pipe, and heat welded steel pipe to 40-60 degrees centigrade by heating furnace, so that the surface of the welded steel pipe is kept dry, because the surface of the welded steel pipe is not containing grease and other dirt, so it can enhance the effect of rust removal. In addition, the surface of the dry welded steel pipe is also beneficial. Steel shot, steel grit and rust and oxide skin are separated, so that the surface of the welded steel pipe after rust removal will be more clean.