Non Standard Forging MOC (SA350-LF2 CL1 vs SA765-II)

[mechmania]

Dear Friends,

Reference:
On High Pressure Vessel where we specify Self Reinforced Nozzle (Other Than STD ANSI LWN) which are mostly Non Standard Forging (Barrel Nozzles).
These Barrel Nozzle can be constructed from Welding 2 Pieces (Boss Welded to FLANGE) or can be made as one piece construction for Barrel and Flange .

DP: 1400 Psig
MDMT: 20F

Question:
1) If it is Made of Two Piece construction (boss welded to Flange), Can the Boss MOC be SA350-LF2 CL1 same as Flange?
2) If it is Made of One Piece Construction than Can it be all SA350-LF2 CL1?

My Understanding was, in Two piece Construction Boss Should be SA765-II and Flange Will be SA350-LF2 CL1.
And in one piece construction the Whole Forging(Boss and Flange) should SA-765-II.

As I read SA-350 is for Piping Components while SA-765 is for Pressure Vessels.

Please share your experience.

Regards,
Mechmania

 

[SnTMan]

mechmania, SA-350-LF2 is widely used for both of your proposed constructions in Sec VIII, Div. 1. SA-105 may be used in some cases. In my experience SA-765 is imposed by client specs, not by Code.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[mechmania]

Thank you SnTMan for quick response.

When i read through the specs I see them as most Identical.

See attached comparison I found that some has put together.

So what prompt these client requirements?

Is there some technical advantage of using SA765-II over SA350-LF2 Cl?

Best regards,

Mechmania

 

[SnTMan]

mechmania, it may be that for the larger forgings testing per SA-765 (Sec 6) is advantageous. I really see no particular reason to pick one over the other , except perhaps that SA-350 is widely available.

The problem with sloppy work is that the supply FAR EXCEEDS the demand