Stainless Steel ERW Black Pipes are a type of steel pipe made from high-quality stainless steel and manufactured using an electric resistance welding process. The black coating on these pipes is a result of the iron oxide formed during the welding process. Stainless Steel ERW Black Pipes are produced from flat steel strips that are formed into a cylindrical shape, then welded longitudinally using high-frequency electrical current. The resulting seam is then welded again to provide additional strength and stability.