Tees are also called pipe fittings tees or tee fittings, tee joints, etc. It is mainly used to change the direction of the fluid, and it is used at the branch pipe of the main pipeline. Can be classified according to pipe diameter. Generally made of carbon steel, cast steel, alloy steel, stainless steel, copper, aluminum alloy and other materials.

Tee is a chemical pipe fitting with three openings, namely one inlet and two outlets; or two inlets and one outlet. The confluence of three identical or different pipelines. The main function of the tee is to change the direction of the fluid. 

Classification of tee steel pipes:

1. Divided by pipe diameter

The ends of the equal diameter tees are all the same size;

The size of the main pipe connection of the tee with different diameters is the same, and the connection size of the branch pipe is smaller than that of the main pipe. 

2. Divided by process

(1) Hydraulic bulging

The hydraulic bulging of the tee is a forming process that expands the branch pipe through the axial compensation of the metal material. The process is to use a special hydraulic machine to inject liquid into the tube blank with the same diameter as the tee, and squeeze the tube blank through the synchronous centering movement of the two horizontal side cylinders of the hydraulic machine. After the tube blank is squeezed, the volume becomes smaller, and the tube blank The pressure of the liquid increases as the volume of the tube blank decreases. When the pressure required for the expansion of the tee branch is reached, the metal material flows along the inner cavity of the mold under the dual action of the liquid pressure in the side cylinder and the tube blank to expand the branch tube.

The hydraulic bulging process of the tee can be formed at one time, and the production efficiency is high; the wall thickness of the main pipe and the shoulder of the tee are increased.

Due to the large tonnage of equipment required for the hydraulic bulging process of seamless tees, it is mainly used in the manufacture of standard wall thickness tees less than DN400 in China. Its suitable forming materials are low-carbon steel, low-alloy steel, and stainless steel with relatively low cold hardening tendency, including some non-ferrous metal materials, such as copper, aluminum, titanium, etc.

(2) Thermoforming

Tee hot press forming is to flatten the tube blank larger than the diameter of the tee to the size of the tee diameter, and open a hole at the part of the stretched branch pipe; the tube blank is heated, put into the forming die, and the tube blank A die for stretching branch pipes is installed inside; under the action of pressure, the tube blank is radially compressed, and during the radial compression process, the metal flows in the direction of the branch pipes and forms branch pipes under the stretching of the die. The whole process is formed by the radial compression of the tube blank and the stretching process of the branch pipe. Different from the hydraulic bulging tee, the metal of the hot-pressed tee branch is compensated by the radial movement of the tube blank, so it is also called the radial compensation process.

Due to the use of heated and pressed tees, the tonnage of equipment required for material forming is reduced. The hot-pressed tee has a wide adaptability to materials, and is suitable for low-carbon steel, alloy steel, and stainless steel; especially for tees with large diameters and thick pipe walls, this forming process is usually used. 

3. Divided by material

Carbon steel tees, cast steel tees, ductile iron tees, alloy steel tees, stainless steel tees, copper tees, aluminum alloy tees, etc. 

4. Divided by production method

Top system, pressing, forging, casting, etc. 

5. Divided by manufacturing standards

National standard, electric standard, chemical standard, water standard, American standard, German standard, Japanese standard, Russian standard, etc., as follows: GB/T12459-2017, ASME B16.9, SH3408, SH3409-96, SH3410-96, HG/ T21635, DL/T 695, SY/T 0510, DIN 2615. 

6. Classified by docking form

Butt welding tee: that is, the tee fittings that are butt welded with the connecting pipe fittings.

Socket tee: insert the connecting pipe into the two ends of the tee, and weld the tee.

Ferrule type tee: that is, each end is a ferrule joint, after inserting the joint, tighten the tee joint.

Threaded Tee: A three-way pipe fitting that is threaded. 

7. Classification by branch form

Main tee: It is a tee fitting for the branch vertical main pipe.

Oblique tee: It is a three-way pipe fitting with a certain angle between the branch pipe and the main pipe. 

Stainless steel tees are pipe fittings and pipe connectors. It is used where the main pipeline is to be branched. The stainless steel tee is divided into equal diameter and different diameter. The ends of the equal diameter tee are all the same size; the size of the main pipe of the reduced tee is the same, and the size of the branch pipe is smaller than that of the main pipe.

Stainless steel reducing tees are widely used in the construction and maintenance of petrochemical, oil and gas, liquefied gas, fertilizer, hydropower plants, nuclear power plants, shipbuilding, papermaking, papermaking, medicine, food hygiene, municipal and other projects.