Carbon steel elbow pipe forming process is the use of special elbow pipe push machine, core die and heating device, in order to achieve the billet set on the mold in the push machine under the push forward movement, in the movement of heating, expanding and tortuous forming process.  Carbon steel elbow pipes deformation characteristics is based on the metal of the volume before and after plastic deformation rules of pipe diameter, concluded that adopted by the diameter of the tube billet is less than the elbow pipe diameter, through the core to control the deformation process of billet mould, making inner arc was tightening metal activity, added to other parts of the thinned by hole diameter, wall thickness uniformity of the carbon steel elbow pipe is obtained.  
 

The forming process of carbon steel elbow pipe fittings has the characteristics of beautiful appearance, uniform wall thickness and continuous operation, which is suitable for mass production of products. Therefore, it has become the main manufacturing method of carbon steel and alloy steel elbow pipe fittings, and it is also used in the manufacturing of stainless steel elbow pipe fittings of some specifications.  The heating method of forming process has medium frequency or high frequency induction heating (heating ring can be multiple or single ring), flame heating and reflector heating, which heating method depends on the requirements of forming products and power conditions.  
 

The rigidity of carbon steel elbow pipe fittings is poor, which is suitable for pressure P ≤4MPa occasions.  The basic process of carbon steel elbow pipe forming skills is: first welding a polygonal polygonal polygonal ring shell or closed at both ends of the polygonal fan shell, after the internal pressure medium is full, the internal pressure is applied, under the effect of internal pressure, the cross section from polygon gradually become round, and eventually become a round ring shell.  There are three types of flange sealing surface: plane sealing surface, suitable for low pressure, medium occasions;  Concave and convex sealing surface, suitable for slightly higher pressure occasions.  
 
Carbon steel elbow pipe fittings (HG20600, GB/T9121, JB/T83) are relatively simple to manufacture, mainly suitable for the pipeline system with corrosive medium;  Different data may be used for elbow fittings and welded rings.  The sealing surface of elbow pipe fittings has a convex surface, concave surface and tenon groove surface.  
 

The part that connects the pipe to the pipe, connected to the end of the pipe.  There are holes in the elbow fittings, and bolts hold the two elbow fittings together.  Gaskets are used to seal between elbow fittings.  It can be cast, threaded or welded.  Elbow fitting connection consists of a pair of elbow fitting, a gasket and a number of bolts and nuts.  The gasket is placed between the sealing surface of the two elbow pipe fittings, and the specific pressure on the surface of the gasket is deformed when it reaches a certain value after tightening the nut, and the uneven place on the sealing surface is filled, so that the connection is tight and leakproof.