ASME VIII Div 1 flat head with blind threaded holes

[jknec]

A vessel design has a 20" diameter head (flat, 2.25" thick) and it requires a 2" opening through which a shaft will pass through. From what I can gather in the code, this opening size is considered insignificant and does not need require reinforcement or additional thickness added to the head. I'm having a hard time trying to figure out if the code allows for a bolt pattern of blind, threaded holes to be placed directly into the flat head around the opening. This would be to avoid welding on a "studded outlet" to the head. Given the thickness of the head compared to the depth of the blind threaded holes, and the small size of the opening, I feel that it would pass a stress analysis, but I don't know how to navigate the code in this case to confirm this. Anyone have advice on how to proceed?

 

[NBrink]

Kind of spitballing here (Can't stand blind holes, so it's not something I have much experience with), but I'm pretty sure UG-43 (d) and (g) is what you're looking for.

 

[jknec]

NBrink, thank you. I think you're correct. Now that I see those two paragraphs I wonder how I missed them before. The depth of the threaded holes is obviously limited, but with a 2.25" thick flat head and 1/2" studs, it leaves plenty of wall thickness.