black metal steel pipe

black metal tube is made of hot rolled or cold rolled strip steel or coil plate as base material by cold bending forming and then by high frequency welding made of square section shape and size of steel. In addition to the thickening of the wall, the corner size and edge flatness of hot rolled extra-thick wall square tube reach or even exceed the level of resistance welding cold forming square tube. Good comprehensive mechanical properties, weldability, cold, hot working and corrosion resistance, with good low temperature toughness. The factory produces tens of thousands of tons of black metal tubes every month and exports them. We have the ability to do anything, quality products and the best ex-factory price.