40 Inch Astm A234 Gr.Wpb Butt Weld Elbow 90 Degree Lr B16.9

40 Inch Astm A234 Gr.WPB 90 Degree LR Pipe Welding Elbow Fittings B16.9

Introduction
Elbow is a kind of pipe fittings commonly used in plumbing installation, which is used to connect at the bend of pipe and to change the direction of pipe.
Other names :90 elbow, right angle bend, love bend, punching elbow, pressing elbow, mechanism elbow, welding elbow, etc.
Purpose: To connect two pipes with the same nominal diameter or different diameter, so that the be turned 90,45,180 and various degrees.
The bending radius is less than 1.5 times of the diameter of the pipe, and 1.5 times of the diameter of the pipe belongs to the elbow.

Process flow
Seamless elbow: elbow is a pipe fitting used at the bend of a pipe. The largest proportion of all pipe fittings used in the pipeline system is about 80. Usually, different forming processes are selected for bends with different materials or wall thickness. The seamless elbow forming process used by the manufacturer is hot push, stamping, extrusion and so on.

Folding Thermal Push
The forming process of hot-push elbow is the process of using special elbow pushing machine, core die and heating device to make the blank set on the die move forward under the push of the pushing machine, and be heated, expanded and bent in motion. The deformation characteristic of hot push elbow is to determine the diameter of pipe billet according to the law of constant volume before and after plastic deformation of metal material. The diameter of pipe billet is smaller than the diameter of elbow. Compensate to other parts of the inner arc thinning due to diameter expansion, thus obtaining a uniform wall thickness elbow.
The hot-push elbow forming process has the characteristics of beautiful appearance, uniform wall thickness and continuous operation, which is suitable for mass production, so it has become the main forming method of carbon steel and alloy steel elbows, and has also been applied in the forming of stainless steel elbows of some specifications.
The heating mode of forming process includes intermediate frequency or high frequency induction heating (heating ring can be multi-ring or single ring), flame heating and reflecting furnace heating. The heating mode depends on the requirements of forming product and energy situation.

Folding stamping forming
stamping forming elbow is the earliest forming process used in batch production of seamless elbow. it has been replaced by hot push method or other forming process in the production of elbow of common specifications, but in some specifications of elbow due to less production quantity, too thick wall thickness or too thin.
The product is still in use when it has special requirements. The punching forming of the elbow adopts the pipe billet equal to the outer diameter of the elbow, and the press is used to press the die directly.
Before stamping, the tube billet is placed on the lower die, the inner core and the end die are loaded into the tube billet, the upper die moves down and begins to press, and the elbow is formed by the constraint of the outer die and the support of the inner die.
Compared with the hot push process, the appearance quality of stamping forming is not as good as that of the former, and the outer arc of stamping elbow is in the tensile state when forming, and there is no extra metal in other parts to compensate, so the wall thickness at the outer arc is about 10% thinner. But because it is suitable for single piece production and low cost, stamping elbow process is mostly used in the manufacture of small batch and thick wall elbow.
Stamping elbows are divided into cold stamping and hot stamping, usually according to the material properties and equipment capacity 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 outer die. After the upper and lower die is molded, the tube billet moves along the gap reserved for the inner die and the outer die under the push rod.
The elbow made by internal and external die cold extrusion process is beautiful in appearance, uniform in wall thickness and small in size deviation. The precision of internal and external die used in this process is high, and the deviation of wall thickness of pipe billet is also harsh.
Medium plate welding
Use a medium plate to make half of the elbow section with a press, and then weld the two sections together. A process such as this is generally used as a bend above the DN700.

Folding other forming methods
In addition to the above three commonly used forming processes, seamless elbow forming also adopts the forming process of extruding the tube billet into the outer die and then passing through the ball shaping in the tube billet. However, this process is relatively complex and difficult to operate, and the forming quality is not as good as the previous process, so it is less used