For a watertube boiler tube with 76 mm O.D. and a wall thickness of 3.25 mm, what is the maximum allowable working pressure?

To determine the maximum allowable working pressure for a watertube boiler tube with the provided dimensions, it's essential to apply the appropriate formula for calculating the pressure capacity of a cylindrical tube. The formula is based on the tube's outer diameter and wall thickness and typically follows the principles outlined in relevant codes, such as the ASME Boiler and Pressure Vessel Code.

In this case, the outer diameter (OD) of the tube is 76 mm, and the wall thickness is 3.25 mm. Using these dimensions, the inner diameter can be calculated as the outer diameter minus twice the wall thickness:

Inner Diameter (ID) = OD - 2 * wall thickness

ID = 76 mm - 2 * 3.25 mm = 69.5 mm

The formula for the maximum allowable working pressure (MAWP) for thin-walled tubes is approximately:

MAWP = (2 * wall thickness * material strength) / outer diameter

Where material strength can be derived from the material properties (often specified as yield strength). Specific material strengths provided in codes will inform the exact output, but for common materials used in boiler tube applications, the yield strength tends to range between significant values reflective of the strength of steel under pressure.

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