Carbon steel elbow, first of all, 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 the outside diameter of the pipe, that is, R = 1.5 D. 

Short radius elbow means that its radius of curvature is equal to the outside diameter of the pipe, that is, R = 1.0 D. 

(D is the diameter of the elbow, the radius of curvature of the R. D can also be used as a times to express.)

If divided by pressure rating, there are about seventeen types, 

which are the same as the U.S. pipe standards, including:Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, 

Sch100, Sch120, Sch140, Sch160, of which the two most commonly used are STD and XS. 

According to the angle of the elbow, there are 45 ° elbow, 90 ° elbow and 180 ° elbow.

The executive standards are GB/T12459-2005, GB/T13401-2005, GB/T10752-1995, HG/T21635-1987, D-GD0219 and so on.

Carbon steel material can be divided into

10# 20# A3 Q235A 20g Q345B 20G 16Mn ASTM A234 ASTM A105 st37 ASTM A403 and so on.

With these materials as raw materials for the production of the elbow can be called carbon steel elbow 

according to the angle: 45 °, 90 °, 180 ° 

These three commonly used elbow, and other engineering needs, can be customized, such as 60 ° or other angles.

Connection with carbon steel pipe: welding, flange connection, threaded connection, socket connection and other forms.

According to the form of technology can be divided into: welded elbow, stamping elbow, casting elbow.

Use: connect two tubes, so that the tube to change direction, to 45 ° or 180 ° and 90 ° direction or other angle turn.

Manufacturing standards: national standard, American standard, Japanese standard, German standard, Russian standard.

Carbon steel elbow of the basic process is: first welded a polygonal cross-section of the polygonal ring shell 

or closed ends of the polygonal fan shell,the internal flushing pressure medium, applying internal pressure, 

under internal pressure from the polygonal cross-section gradually become round, and ultimately become a circular ring shell.

According to the need, a circular ring shell can be cut into four 90 ° elbow or six 60 ° elbow or other specifications of the elbow, 

the process is suitable for the manufacture of elbows 

and elbow diameter ratio of any specifications of the elbow greater than 1.5 times the inside diameter of any large elbow,

is the ideal method for the manufacture of large carbon steel elbow.

The advantages of the carbon steel elbow production process are mainly manifested in the following aspects.

(1) no billet as raw material, can save the cost of pipe making equipment and molds, 

     and can get any large diameter and relatively thin wall thickness of carbon steel elbow.

(2) billet for flat or curved surfaces can be extended, so the material is simple, easy to ensure accuracy, assembly 

     and welding convenience.

(3) As a result of the above two reasons, can shorten the manufacturing cycle, production costs are greatly reduced. 

     Because it does not require any special equipment, especially suitable for on-site processing of large carbon steel elbow.

(4)Carbon steel elbow is suitable for pipeline series in petroleum, natural gas, chemical, water and electricity, 

    construction and boiler industries.