ASME B16.9 ASTM B363 Titanium Equal Tee

Production process of pipe tee

Hydraulic bulging

The hydraulic bulging of the tee is a forming process in which the branch pipe is expanded by 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 of pipe tee, and to simultaneously press the two horizontal side cylinders of the hydraulic machine to press the tube blank, the volume of the tube blank becomes smaller, and the tube blank is compressed. The liquid becomes smaller as the volume of the tube blank becomes smaller, and when the pressure required for the expansion of pipe tee branch pipe is reached, the metal material flows along the cavity of the mold under the double action of the liquid pressure in the side cylinder and the tube blank to swell out of the branch pipe.
pipe tee hydraulic bulging process can be formed at one time, and the production efficiency is high; the main pipe and shoulder wall thickness of pipe tee are increased.
Due to the large tonnage of the equipment required for the hydraulic bulging process of the seamless tee, it is currently mainly used for the manufacture of standard wall thickness tees smaller than DN400. The suitable forming materials are low carbon steel, low alloy steel and stainless steel with relatively low cold work hardening tendency, including some nonferrous metal materials such as copper, aluminum and titanium.

Hot press forming

Pipe tee hot press forming is a process in which a tube blank having a diameter larger than a Pipe tee diameter is flattened to a diameter of a tee.
a hole is opened in the portion of the stretching branch pipe; the tube blank is heated, placed in a forming mold, and a die of the stretching branch pipe is loaded into the tube blank; under the action of the pressure, the tube blank is radially compressed and compressed in the radial direction. During the process, the metal flows toward the branch pipe and forms a branch pipe under the drawing of the die. The entire process is formed by the radial compression of the tube blank and the stretching process of the branch portion. Different from the hydraulic bulging tee, the metal of the hot-pressed Pipe tee branch pipe 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 tees, the tonnage of the equipment required for material forming is reduced. The hot press tee has wide adaptability to materials, and is suitable for materials of low carbon steel, alloy steel and stainless steel; especially for tees with large diameter and thick wall, this forming process is usually adopted.
Reasons and solutions for the deviation of the angle of pipe tees during the manufacturing process
(1) The pipe tee is prone to angular offset, the surface is not flat, the diagonal of the nozzle is not equal, and the bite is not strict. The main reasons for this are:

• 1) The straight angle of the inner and outer arcs is not accurate. The thickness of the material itself is not considered. After the finished product is formed, the phenomenon that the outer arc piece is short and the inner arc piece is long is formed, which affects the angle.
• 2) Two planes with curved lines are ruled.
• 3) Small holes appear in the outer corner of pipe tee outer arc.
• 4) The width of the joint angle bite is not equal, and the force at the bite is uneven.

(2) The main prevention methods are:

• 1) Find the material with a corrected square. The pipe tee is unfolded with the dimensions R1 and R2, and the width should be increased by the margin of the hem to prevent the pipe tee from being installed improperly.
• The lengths of the back and inside of the elbow are 1.57R1 and 1.57R2, respectively. The accuracy of the arc should be guaranteed.
• 2) After the two large pieces are unrolled, the ends of the sheets should be strictly angled. The two flat sheets with curvature are overlapped, and the shape coincidence error is checked and the deviation is allowed.
• Adjustment.
• 3) Small holes appearing in the outer arc corner of pipe tee, and can be repaired by soldering for the stainless steel plate.
• 4) When making a manual bite, make sure the width is appropriate, ensure the size of the tee, and ensure that the force is even when the mouth is bitten.

Factory inspection of pipe tee

The chemical composition of pipe tees shall be checked and accepted according to the material list. If there are special requirements, the re-inspection may be carried out according to the standard requirements. The arbitration backwashing method is in accordance with the relevant standards.
The surface of the tee should be free of cracks, pores, undercuts, slag inclusions, and the inside and outside must be smooth. There should be no scratches, negative pits and straightening defects that are beyond the tolerance of the wall thickness of the steel pipe. The fracture should be free of burrs. The appearance inspection of the pipe tee is visually inspected under good daylight illumination (a 5x magnifying glass is available).
In terms of size, the dimensional inspection of the tee is measured with a measuring instrument of corresponding accuracy.
Appearance test: pipe tees shall be submitted for acceptance in batches. Each batch shall consist of pipe fittings of the same grade, the same size and the same process. The number of pipe tees of each batch shall not exceed a certain requirement; 400 shall be 400 for nominal pass or less. Root; 200 of the nominal passages greater than 25mm.