Tee Fittings: The Forming Process Of Extruded Tee Fittings
Tee fittings are very part of the large pipe fittings, usually in petroleum and chemical pipeline engineering. The most widely used types for pipelines engineering are cast tee pipes, forged tee pipes, T-welded tee pipes, and extruded tee pipes. We look at each of the technologies and why extrusion is the best tee fittings forming technology today.
Cast Tee Pipes
Because the quality of the foundry tee can be difficult to get, installation processes usually include a lot of repair welding. This could directly affect the progress of the whole project. The developed defects of the foundry tee may also not be easy to check. The possibility of leakages is very high for cast tee pipes, which makes them unsuitable for petroleum and chemical industries.
Forged Tee Pipes
The forging tee has a large body. The level of materials and work involved in making the forged tee pipes is too much. There is a lot of cutting, and the process will require a lot of steel. It is a complicated process, and the high cost makes it less popular.
T-Welded Tee Pipes
The T-welded tee types forms by opening a saddle-shaped weld on the mother pipe and then directly welded to the branch pipe section. The biggest problem with these types of T-welding tee types is T-joint weakness. The welded part of the joint will become the biggest weakness of the entire fitting. These tee fitting also uses a large amount of welding material, and the labor intensity is very high. This makes tee fittings made from this method expensive.
Extruded Tee Pipes
Extrusion tee has no weld seam, and they have good overall strength. The high production efficiency and relatively low production cost are other advantages of the extrusion tee. When you compare it with the above methods, it stands out. Extrusion tee has so many advantages and is currently the best choice for pipeline engineering tasks such as petroleum and chemical industries.
There are two main forming processes for seamless extrusion tee. The first one is the hot press forming process, and the other one is the cold extrusion forming process. The seamless three-way cold extrusion forming process, also known as the bulging hydraulic process, is the most common today. The branch pipe is expanded by the axial compensation of the metal material.
Seamless three-way cold extrusion
The process uses a special tee machine that injects liquid into a tube blank. The tube blank, which has the same diameter as the main tee pipe, is filled with fluid to squeeze it through two horizontal side cylinders of the tee machine. The squeezing changes the volume of the tube blank since pressure increase in the liquid inside reduce the tube’s volume.
When the pressure expansion for the branch tube is reached, the metal material will move along the mold cavity under the dual action of the side cylinder and the liquid pressure in the tube blank. Flow and expand out of the branch pipe. The whole process is formed by the axial compression of the tube blank and the bulging process of the branch part. The metal of the seamless cold extruded tee branch pipe is compensated by the axial movement of the tube blank. That’s why it is also called the axial compensation process.
The seamless cold extrusion tee process is done at one time. The production efficiency is higher, while the wall thickness and shoulders of the tee-main pipe are increased. Carbon steel and stainless steel are widely used materials due to the low tendency of cold work hardening, including some non-ferrous metal materials like titanium, copper, and aluminum.