Weld Overlayed Dimension of RTJ groove in Standard Flanges 1

[Shanamo]

Dear forum members
Greetings of the day !
I am a bit not clear on the weld overlay of RTJ groove of standard flanges. If for instance, the ring groove is applied with 5mm SS316L WO then as a consequence of it all the groove dimensions change. Then in this case how a standard ring ( octogonal/oval ) as per STD B16.20 would fit in the overlayed groove.
Moreover, as an alternate if we machine increase the standard groove size before overlay to adjust for overlay thickness then will the STD flange not become a non standard thereby further requiring compliance to APP-2 ?
Kindly suggest.
Regards
Shanamo

 

[SnTMan]

Shanamo, you need to maintain the standard groove dimensions so you can use standard gaskets.

So, as you noted, you machine the existing groove/facing as required, apply the WOL and re-machine the finished groove/facing.

I know this is done regularly, I don't know any formal basis permitting it. Sec VIII, Div. 1, Apx 2 is unlikely to be of any help.

Regards,

Mike

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

 

[jte]

Shanamo-

The B16.5 rating is based on flange thickness, not groove dimensions. You could machine off the entire "ring groove height" area and you'd have a perfectly B16.5 compliant flat face flange. So, one option for you is to maintain that flange thickness dimension, machine the edges of the groove wider being careful to not make the groove deeper, weld overlay the edges and bottom and upper wetted surface, then machine down to a clean finish. This changes the overall height of the flange, so you'll need somewhat longer studs, and be careful about mating piping etc.

ASME PCC-2 discusses this type of work, but more in a remediation to flaws perspective. It's in Part 3, not Part 2 as you might expect, since it is in the flange machining article.

 

[Shanamo]

Its clear to me now.
Thank you SnTMan and jte for your time and valuable suggestions.
Shanamo

 

[jbeckhou]

SnTMan is correct. Rough out ring groove, NDE, weld per approved WPS, machine to print, NDE, inspect. What jte said is crazy and never done.

Petrotrim Services, LLC

http://www.petrotrim.com

 

[jte]

What jte said is crazy and never done.

To each his own. Perhaps if jbeckhou had added "...in my experience." I could agree with him/her. But, to state an absolute "never done" is incorrect. Since in my experience, it has been done, without excessive insanity, and with successful long runs after the modification. So, whatever. Just consider the source

http://www.eng-tips.com/userinfo.cfm?member=jbeckhou

with one "great post" vote in this forum vs. the guy with 152 (click on my handle in this post for the link). A more persuasive argument against a flange modification might include something of a technical nature; at least that would give forum readers something to ponder and an engineering basis for their own decision making.