According to the standard production can be transformed into:

Material：

Carbon steel: ASTM/ASME A234 WPB, WPC

Alloy: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP 91-WP911, 15Mo3 15CrMoV, 35CrMoV

Stainless steel : ASTM/ASME A403 WP 304-304L-304H-304LN-304N ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H

Cryogenic steel : ASTM/ASME A402 WPL3-WPL 6

High performance steel: ASTM/ASME A860 WPHY 42-46-52-60-65-70

Cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon-chromium leaching, PVC, PPR, RFPP(reinforced polypropylene), etc.

The production method can be divided into: pushing, pressing, forging, casting, etc.

According to the manufacturing standards, it can be divided into: national standard, electric standard, ship standard, chemical standard, water standard, American standard, German standard, Japanese standard, Russian standard, etc.

According to its curvature radius to divide: can be divided into long radius elbow and short radius elbow.  Long radius elbow refers to its radius of curvature is equal to 1.5 times the outer diameter of the pipe, namely R=1.5D;  A short radius elbow has a radius of curvature equal to the outer diameter of the pipe, i.e., R=1.0D.  (D is elbow diameter, R is curvature radius).

According to the pressure level, there are about 17 kinds of pipe standards, which are the same as those of the United States, such as Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS;  Sch80, SCH100, Sch120, Sch140, Sch160, XXS;  The two most commonly used are STD and XS.

According to different shapes, it can be divided into: groove elbow, clamp sleeve elbow, double bearing elbow, flange elbow, reduced diameter elbow, inside and outside elbow, punching elbow, push elbow, socket elbow, butt welding elbow, inner wire elbow, etc.

The conventional classification：

In a torsion Angle, Angle of cutting sleeve type has the edge Angle, fast loading of bend and arrange ushering elbow, flange, elbow, 180 ° bend, double elbow, ChanCheng elbow, socket bend, reducing elbow, seamless elbow, butt welding elbow 45 °, 90 ° elbow, elbow combination tee female elbow, stamping elbow, elbow push system, high pressure Angle Wear-resisting bend, mechanical elbow , flange elbow, groove elbow, three-dimensional elbow, external thread elbow, thread elbow, special elbow,  waterproof elbow.