20 # steel pipe made of 20 steel, usually 20 seamless steel pipe 20 # steel pipe material: high-quality carbon structural steel, 20 # steel grades: 20 Steel Standard: GB / T 699-1988 characteristics and scope of application: strength than the 15th steel is slightly higher, little quenching, temper brittleness. Cold deformation crack-prone high plasticity, usually for bending, rolling, bending and machining hammer arch, arc welding and contact welding welding performance when welding thin, form-critical or complex shape parts. The Machinability drawn or normalized condition than the annealed condition, generally used for uneven force manufacturing high toughness requirements.