Elbow according to its radius of curvature can be divided into long radius elbow and short radius elbow. Long radius elbow means that its radius of curvature is equal to 1.5 times of the outer diameter of the pipe, i.e. r = 1.5D. A short radius elbow means that its radius of curvature is equal to the outer diameter of the pipe, i.e. r = D.

Intuitively, the short radius elbow is much shorter than the long radius elbow, and the bending radius of the elbow is very fast. The long radius elbow is the most commonly used one. Generally, it is also long radius by default. The long radius elbow will be used in the place with high pressure or high flow rate. If the resistance requirements of solid conveying pipeline are strict, the elbow with larger radius should be used. Short radius is usually used in low-pressure fluid or where elbows are limited.

The short radius elbow is made of stainless steel, carbon steel and alloy steel.