The welded elbow of steel hot pressing or forging molding elbow form of connection is directly to the elbow and pipe butt welded elbow manufacturing standards generally GB/T12459, GB/T13401 ASME B16.9, SH3408, SH3409, HG/T21635, HG/T21631, SY/T0510, GB/T10752-1995. The welded elbow by its radius of curvature can be divided into welded elbow long radius and short radius welded elbow. Butt welding of long radius elbow radius of curvature equal to 1.5 times the pipe diameter, i.e. R = 1.5D. The welded elbow short radius curvature radius equal to the outer diameter of the tube, R = 1D. Wherein D is the diameter of the welded elbow, R radius of curvature. Pressure rating, about seventeen kinds of tubes and the United States is the same standard: of Sch5s Sch10s, Sch10, SCH20, SCH30, SCH40S, STD, Sch 40 has an Sch60 Sch80s, XS; Sch80, Sch10, Sch120, Sch140, Sch160, XXS, one of the most common STD and XS. At the angle of the elbow, 45 degree welded elbow, 90 degree welded elbow and a 180-degree welded elbow. Material: carbon steel, alloy steel and stainless steel. The straight seam elbow straight seam steel pipe billet heated to high temperatures push the system unit and the different types of core head processed into. The elbow push system needs normalizing heat treatment, the machined port, wall thickness to be left burning and machining allowances. Usually the balance of the elbow theory 10% to 20% of the wall thickness. Elbow wall thickness delta-sectional diameter D ratio is smaller, the mold fit performance better, but the elbow arc more easily wrinkling. According to the characteristics of metal plastic deformation constant volume, made of push-shaped constant wall thickness (actually micro thinning), equal to the length of the elbow arc length of tube, the tube push the system is derived molding?? Straight seam elbow 30 degrees straight seam elbow 45 degrees straight seam elbow? straight seam elbow 60 degrees 90 degrees 120 degrees elbow straight seam straight seam elbow 180 degrees straight seam elbow? Material can be divided into: Carbon steel straight seam elbow stainless steel elbow straight seam steel straight seam elbow. ? Bending radius: 1 times 1.5 times 2 times. Diameter: DN15-DN1000 wall thickness; 3mm - 18mm straight seam elbow. Standard: GB, ship standard, German standard, American standard, Japanese standard, non-standard electric scalar Ministry of Chemical Industry standards.