Tees are widely used in water supply and drainage systems, pipelines of steam and hot water, main and field oil and gas pipelines, process pipelines in the oil, gas, chemical and petrochemical industries.For tees production are used carbon and alloy steels of ordinary quality, high quality, which have cold-resistant and heat-resistant properties, as well as resistance to aggressive media.
The shape and technical requirements of the production are regulated by corresponding GOST, OST and Technical specifications.
According to the shape are distinguished:
- transition tees (different diameters of the main and branches);
- straight (equal to the diameter of the main and branches).
- Stamped seamless tees
They are produced by hot deformation of billets on the corresponding equipment (the press). In the manufacturing process it is important to choose the right strain modes in order to avoid unacceptable thinning of the neck, the appearance of micro cracks and to provide the necessary height and radius of tie-in. Seamless pipes are used as blanks.
- Welded tees
Made of tubular billet and sheet metal by welding the branch (fitting) to the main line (body). Special attention is paid to the manufacturing of cutting blanks for proper joining of welded parts of the tee. They are used in systems with operating pressures up to 4 MPa. Also to reinforce the connection of fitting-body are used special steel plates. It improves operational properties of parts and their use in piping systems with increased pressure.
- Stamp-welded tees
For their manufacturing is most commonly used method of hot stamping of sheet metal. Metal sheets and welded tubes are used as blanks. This type is widely spread in main and field pipelines in oil and gas industry with operating pressure up to 9.8 MPa. They are made with a diameter up to 1420mm.
- Turned tees
Produced by machine processing of the blank. Bar sections or forging (with normalized mechanical properties) are used as blank. This type is widely used in high pressure pipeline systems up to 100MPa.