If your vessel must comply with any of the Pressure Vessel standards, then I agree with MJCronin and you should look into using a formed head rather than a flat plate. If your vessel is non-code, then you can use the procedure described by Jstephen or use Rork's Formulas for Stress and Strain.
I am facing the same dilemma when trying to drill a single opening in a blank flange. Since applying the Section VIII Div. 1 Appendix 2 formulae results in a thicker thickness than the one for a standard B16.5 flange, then I have decided to fabricate a flange using the Section VIII calculated...
The specific requirment for RT is given in ASME B31.3 Paragraph 3.41.4.(b) which states: "Not less than 5% of circumferential butt and miter groove welds shall be examined fully by random radiography in accordance with para. 344.5 or by random ultrasonic examination in accordance with para...
roker:
Take a look to the ASME Code B31.1 Appendix II. The whole appendix is dedicated to this topic. It has some general guidelines for steam applications
