If a blank, full-hemispherical head is made of SA-515-65 and must withstand 1800 kPa at 425°C, what is the required thickness?

To determine the required thickness of a blank, full-hemispherical head made of SA-515-65 steel that must withstand a pressure of 1800 kPa at a temperature of 425°C, we can apply the formula for the thickness of a pressure vessel head.

The thickness required for a spherical head can be calculated using the following formula:

[ t = \frac{PR}{2SE} ]

Where:

• ( t ) = required thickness

• ( P ) = internal pressure (in the same units as the yield strength)

• ( R ) = radius of the head (assumed to be known or provided)

• ( S ) = maximum allowable stress (considering temperature reduction factors)

• ( E ) = joint efficiency (assumed to be 1 if the joint is perfect)

For SA-515-65, you would typically reference tables that provide the allowable stress of this material at the specified temperature. At 425°C, the stress value would be lower than its ambient temperature rating due to the effects of heat.

Given the internal pressure of 1800 kPa and the appropriate allowable stress for SA-515-65 at 425°C, the calculations would produce a