Cold Rolled Steel Pipes have square hollow section and circular section (round hollow section). The material is cold rolled carbon steel strap with wall thickness 0.6mm to 2.0mm. When cold-rolled steel strap is heated to the annealing temperature, the surface color will turn black due to high temperature contact with air, which is called black stripping. The physical properties become soft, which is convenient for further welding to make steel pipes. The common hardness is 57HRB, and it can also be reduced to different hardness as needed.
The steel pipe material is non-alloy low carbon steel. Pipe production technical method is ERW welded with longitudinal seam. Product standards are able to comply with ASTM A500, ASTM A53, ASTM A795, BS1387, BS EN10255, EN 10219, BS 1139, BS 39.