Black steel pipe is the un-coated steel and is also called as black steel.
The dark color comes from the iron-oxide formed on its surface during manufacturing. When steel pipe is forged, a black oxide scale forms on its surface to give it the finish which is seen on this type of pipe.
Galvanised Steel are those steel that has been covered with a layer of zinc metal.
Galvanised steel pipe is that steel that has been covered with a layer of zinc metal. During galvanizing, steel is immersed in a molten zinc bath, ensuring a tough, uniform barrier coating. Galvanised pipe is covered with a zinc material to make the steel pipe more resistant to corrosion.
Difference in appearance
The primary purpose of black steel pipe is to carry propane or natural gas into residential homes and commercial buildings. The pipe is manufactured without a seam, making it a better pipe to carry gas. The black steel pipe is also used for fire sprinkler systems because it is more fire-resistant than galvanised pipe. The primary use of galvanized pipe is to carry water to homes and commercial buildings. The zinc also prevents the buildup of mineral deposits that can clog the water line. Galvanised pipe or GP pipes is commonly used as scaffolding frames because of its resistance to corrosion.
Difference in problems
The zinc on galvanised pipe flakes off over time, clogging the pipe. The flaking can cause the pipe to burst. Utilizing galvanised pipe to carry gas can create a hazard. Black steel pipe, on the other hand, corrodes more easily than galvanised pipe and allows minerals from water to build up inside it.