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 press to inject liquid into the tube blank with the same diameter as the tee, and to extrude the tube blank through the synchronous centering movement of the two horizontal side cylinders of the hydraulic press. When the pressure required for the expansion of the tee branch pipe is reached, the metal material flows along the cavity of the mold under the dual action of the side cylinder and the liquid pressure in the pipe blank to expand the branch pipe.

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 tee, it is mainly used in the manufacture of standard wall thickness tee less than DN400 in China. The applicable forming materials are low carbon steel, low alloy steel and stainless steel with relatively low cold work hardening tendency, including some non-ferrous metal materials such as copper, aluminum, titanium, etc.

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2. Hot press forming

Three-way hot press forming is to flatten the tube blank larger than the diameter of the three-way to the size of the diameter of the three-way, and open a hole in the part of the drawn branch pipe; The die for drawing the branch pipe is loaded into it; the tube blank is radially compressed under the action of pressure, and the metal flows in the direction of the branch pipe during the radial compression process and forms the branch pipe 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 pipe is compensated by the radial movement of the tube blank, so it is also called the radial compensation process.

Since the tee is pressed after heating, the tonnage of the equipment required for material forming is reduced. Hot-pressed tee has wide adaptability to materials and is suitable for low carbon steel, alloy steel and stainless steel materials; especially for tee with large diameter and thick wall, this forming process is usually used.