How much force the steel tube can bear can be calculated through experiments.
P = 2T [S] / D, where: p-water pressure in steel tube, MPa; D-inner diameter of steel tube, mm; [S] - allowable tensile stress intensity of steel tube, MPa, T-wall thickness of steel tube, mm.

The origin of this formula is to take a unit length of water pipe, cut it open, take out half of it, and study the balance between the water pressure acting on it and the pipe wall tension, so as to obtain this formula.

This formula can be used for seamless steel tube, welded steel tube and stainless steel tube, but the allowable tensile stress intensity [S] of steel tube in the formula is different, and the [S] of welded steel tube also depends on the quality of weld.

It should be emphasized that the bearing pressure here refers to the water pressure inside the steel tube, not the pressure outside the steel tube, and the bearing pressure outside the steel tube should be considered separately.