Coated steel pipes have excellent corrosion resistance and relatively low friction resistance. Epoxy resin powder coated steel pipes are suitable for conveying media such as water supply and drainage, seawater, warm water, oil, gas, etc., while polyethylene coated steel pipes are suitable for conveying media such as drainage, seawater, oil, gas, etc. The common colors for coated steel pipes are black, gray, blue, red, white, and green.