Butt weld elbow is a steel hot-pressed or forged elbow, and its connection form is to directly butt-weld the elbow and the steel pipe.
The main manufacturing standards of butt weld elbows are generally GB/T13401-2005, GB/T12459-2005, ASME B16.9, SH3409, HG/T21635, HG/T21631, SY/T0510, GB/T10752-1995.

Classification of butt weld elbows:
(1) Butt weld elbows can be divided into long radius butt weld elbows and short radius butt weld elbows according to the radius of curvature. The radius of curvature of the long radius butt weld elbow is equal to 1.5 times the outer diameter of the pipe, that is, R=1.5D. The radius of curvature of the short radius butt weld elbow is equal to the outer diameter of the pipe, that is, R=1D. In the formula, D is the diameter of the butt weld elbow, and R is the radius of curvature. If there is no special description, the 1.5D elbow is generally used.
(2) According to the pressure level, there are about seventeen kinds, which are the same as the American standards, including: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160, XXS, of which the most commonly used are STD and XS.
(3) According to the angle of the elbow, there are 45 degree butt weld elbow, 90 degree butt weld elbow, 180 degree butt weld elbow and other elbows with different angles.
(4) Materials are: carbon steel, alloy steel and stainless steel.