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How to make elbow?

Jul. 26, 2019

How to make elbow? Here the Stainless Steel Pipe Fittings supplier would like to share with you.

Push hot forming

Hot push elbow forming process is the process of using special elbow pusher, mandrel and heating device to make the blank covered on the die move forward under the push of the pusher. Hot push bend deformation characteristics are based on volume before and after plastic deformation rule of metal materials determine the pipe diameter, pipe diameter bend diameter, through the core module and control the deformation of the process, make the inner arc compressed metal flow, the compensation to other parts of the thinned by hole diameter, wall thickness uniform Angle is obtained.

Hot push elbow forming process has the characteristics of beautiful appearance, uniform wall thickness and continuous operation, and is suitable for mass production.

The heating methods of forming process include medium frequency or high frequency induction heating (heating coil can be multiple or single), flame heating and reflector heating. The heating method depends on the requirements of forming products and energy conditions.


Stamping forming elbow is the earliest forming technology used in mass production of seamless elbow, in the common specifications of elbow production has been hot push or other forming technology instead, but in some specifications of elbow due to the production quantity is small, the wall thickness is too thick or too thin.

Alloy Steel Elbow

The product is still in use when there are special requirements. The pipe blank with the same diameter as the elbow is used to press the elbow directly in the die.

Before stamping, the tube billet is placed on the lower die, the inner core and end die are loaded into the tube billet, the upper die starts to press downward, and the elbow is formed through the constraint of the external die and the support of the internal die.

Compared with the hot pushing process, the appearance quality of stamping is not as good as the former. The outer arc of the stamping Alloy Steel Elbow is stretched when forming, and there is no extra metal in other parts to compensate, so the wall thickness at the outer arc is reduced by about 10%. However, due to the characteristics of single piece production and low cost, the punching elbow technology is mostly used for the manufacture of small batch, thick wall elbow.

Stamping elbow cold stamping and hot stamping two kinds, usually according to the nature of materials and equipment ability to choose cold stamping or hot stamping.

The forming process of cold extrusion elbow is to use a special elbow forming machine to put the tube billet into the external die. After the upper and lower die are closed, the tube billet moves along the gap reserved by the internal die and the external die to complete the forming process.

The elbow made by internal and external die cold extrusion technology is beautiful in appearance, uniform in wall thickness and small in size deviation, so the stainless steel elbow, especially the thin-walled stainless steel elbow forming, is made by this technology. The precision of internal and external mould used in this process is high. The deviation of wall thickness of tube billet is also demanding.

Medium plate welded

Press the middle plate to make half of the elbow section, then weld the two sections together. Such a process is generally used for more than DN700 elbow.