Coated composite steel pipes are often coated with epoxy resin powder, which is 100% solid, solvent-free, and pollution-free. The powder utilization rate during the coating process can reach over 95%, making it a widely used anti-corrosion coating for the inner and outer walls of buried steel pipelines. Seamless or welded steel pipes used in coated composite steel pipes are subjected to sandblasting and shot blasting for rust removal before being heated to a certain temperature in a heating furnace