Large welded elbow Description: welded elbow is forged steel molding or thermoforming of the elbow, which is directly connected in the form of elbow and pipe welding, butt welding elbow major manufacturing standards generally GB / T12459, GB / T13401, ASME B16.9, SH3408, SH3409, HG / T21635, HG / T21631, SY / T0510. Welded elbow generally have 45-degree elbow, 90 degree elbow, 180-degree elbow, materials are carbon steel, alloy steel and stainless steel. Elbow classification: (1) by its radius of curvature of the elbow points, can be divided into long and short radius bend radius bend radius of curvature of long radius elbows equal to 1.5 times the pipe diameter, that is R = 1.5. D. Short radius of curvature equal to the radius of the elbow pipe diameter, i.e., R = D. where D is the bend diameter, R is the radius of curvature. (2) If the pressing force rating points, about seventeen, and American standard pipe is the same, there are: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS, Sch80, Sch100, Sch120, Sch140, Sch160, XXS, the most commonly used is STD and XS two kinds. (3) divided by the elbow angle, 45 degree elbow, 90 degree and 180 degree elbow bend.