All four-way tees at SITONG have opposite dimensions; the main tees of the unequal diameter tees face each other, while the branch tees are smaller by ten millimeters than the main tees. The stainless steel four-way tee is a pipe fitting used at pipe branch points. For four-way tees manufactured with seamless pipes, the current commonly used processes are hydraulic expansion and hot pressing. The hydraulic expansion of the hydraulic expansion four-way tee is a forming process that involves expanding the branch pipe by compensating the axial expansion of the metal material.

The process involves using a hydraulic press, where a liquid is injected into a billet with a diameter equal to that of the four-way diameter. The billet is then simultaneously compressed through the movement of the two horizontal cylinders of the hydraulic press. As the billet is compressed, its volume decreases, causing the pressure of the liquid inside to rise. When the pressure reaches the required level for the four-way branch to expand, the metal material expands into the branch cavity under the combined action of the pressure in the side cylinder and the liquid pressure within the billet.

The four-way hydraulic expansion red art can be formed in one go, offering high production efficiency; the thickness of the main and shoulder walls of the four-way has been increased.