What is the maximum allowable working pressure for a watertube boiler tube with a 73.5 mm O.D. and 4.71 mm wall thickness?

To determine the maximum allowable working pressure of a watertube boiler tube, the dimensions of the tube (outer diameter and wall thickness) and the material properties must be taken into account.

In this case, the outer diameter is given as 73.5 mm and the wall thickness is 4.71 mm. The internal diameter can be calculated by subtracting twice the wall thickness from the outer diameter, which results in an internal diameter of approximately 64.08 mm.

The formulas used for calculating the maximum allowable working pressure are often based on the Barlow's formula for thin-walled cylinders, which states that the maximum pressure is a function of the material's yield strength and the tube's dimensions.

For most steel materials used in boiler tubes, the yield strength typically ranges around 250 MPa to 450 MPa. Using commonly accepted values for yield strength and considering safety factors, the calculated maximum allowable working pressure for the given dimensions aligns with what is found as 9.921 MPa.

This value is derived from the relationships established for pressure tanks and tubular structures under pressure. The calculations confirm that the chosen answer accurately reflects the safe operational limits following industry standards for watertube boilers. Thus, based on the input