The production process of epoxy resin coated steel pipe

epoxy coated steel pipe first pre-treats the base pipe--polishing the steel pipe (advantages: automatic spraying makes the coating on the inner and outer walls of the base material uniform, and the leveling property is good. it meets the cj/t120-2008 standard and gb/t5135 .20 --- 2010 standard --- put the polished steel pipe into the electric oven for preheating, when the temperature reaches 230°~250° (generally about one and a half hours of preheating)) --- for the preheated pipes are coated - after coating, put into the curing box for curing (when the temperature reaches 200 degrees, keep for 15 minutes) - finished product. after spraying, the heating equipment is preheated to 180 degrees to cure the sprayed substrate. advantages: when spraying, the epoxy resin powder has not been completely fused to the inner and outer walls of the substrate. after 30 minutes of preheating and curing, the epoxy the curing agent in the resin is completely cured, making the coating adhesion on the inner and outer walls stronger.

in my country, the earliest base pipes coated with epoxy resin inside and outside were all galvanized steel pipes. later, it was found that the galvanized layer on the inner wall was not good for improving the adhesion of the inner coating, but had an impact. at the same time, it increased the cost of the galvanizing process. to improve the inner wall for the adhesion of the coating, the inner galvanizing process of the galvanized steel pipe also needs to adopt a dezincification process, which increases the cost again and also causes a waste of energy. therefore, there are also welded steel pipes that are directly coated. the inner and outer epoxy resin steel pipe base pipes should be sand blasted before plastic coating to remove rust, oil stains, and galvanized layers on the metal surface, which is generally called surface pretreatment. the construction industry has no quantitative index requirements for surface pretreatment, and the petroleum industry is relatively more specific.