Seamless elbow process flow

Seamless elbow process flow

Seamless elbow: The elbow is a pipe fitting used at the bend of the pipe. In all the pipe fittings used in the pipeline system, the proportion is large, about 80%. Usually, different forming processes are selected for elbows of different materials or wall thickness. The forming processes of seamless elbow commonly used by manufacturers include hot pushing, stamping, extrusion and so on.

Hot push forming of seamless elbow: The forming process of hot push elbow is a process of using common elbow machine, core die and heating device to make the blank on the mold move forward under the push of the pushing machine, which is heated, expanded and bent in the movement. The deformation characteristic of hot push elbow is to determine the diameter of the tube blank according to the law of constant volume before and after plastic deformation of the metal material. The diameter of the tube blank is less than the diameter of the elbow. The deformation process of the blank is controlled by the core mold, so that the compressed metal flow in the inner arc can be compensated to the other parts thinned by the expansion, so as to obtain the elbow with uniform wall thickness.

Hot push elbow forming process has the characteristics of beautiful appearance, uniform wall thickness and continuous operation, suitable for mass production, so it has become the main forming method of carbon steel and alloy steel elbow, and is also used in some specifications of stainless steel elbow forming.

The heating method of the forming process has medium frequency or high frequency induction heating (heating ring can be multiple or single ring), flame heating and reflection furnace heating, which heating method depends on the forming product requirements and energy situation.

Forming by stamping

Stamping forming elbow is a forming process applied to mass production of seamless elbow. It has been replaced by hot push or other forming processes in the production of common specifications of elbow, but in some specifications of elbow due to the production quantity is small, the wall thickness is too thick or too thin.

Seamless elbow products are still in use when there are special requirements. The stamping forming of the elbow is made of a tube blank equal to the outer diameter of the elbow, which is directly pressed by a press in the die.

Before stamping, the tube blank is placed on the lower die, and the inner core and end die are loaded into the tube blank. The upper die moves downward to press the tube blank, and the elbow is formed by the constraint of the outer die and the support of the inner die.

Compared with hot pushing process, the appearance qual