All four-way tees at SITONG have opposing dimensions; the main tee dimensions of the tapered four-way are opposing, while the branch tee dimensions are 10mm smaller than the main tee dimensions. The stainless steel four-way tee is a pipe fitting used at pipe branching points. For four-ways manufactured with seamless tubes, the current commonly used processes are hydraulic expansion and hot pressing. The hydraulic expansion of the hydraulic expansion four-way is a forming process that expands the branch pipe through the axial compensation of the metal material.

The process involves using a hydraulic press to inject liquid into a billet with a diameter equal to that of the four-way fitting. The billet is then simultaneously compressed by the press's two horizontal side cylinders. As the billet is compressed, its volume decreases, causing the liquid inside to increase in pressure. When the pressure reaches the level required to expand the four-way fitting's branch, the metal material flows and expands into the branch under the combined pressure of the side cylinder and the liquid inside the billet.

The four-way hydraulic bulging 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.