ASME flange surface

[anolan23]

Hi,
Please see photo of a 2" 600# RFWN flange surface. This piping unit is intended to be built to ASME B31.3 and the flanges meet ASME B16.5 which B31.3 references. A spiral wound gasket would be used to mate to another flange.

My question:
Does having weld metal on the flange surface automatically put us out of code compliance? My initial reaction is definitely yes, but want to get another opinion. If you could point to an appropriate paragraph that backs up your statement, please do include it.

 

[pennpiper]

anolan23,
I strongly urge you to give us help on your Problem:
1, Give us more pictures (i.e. the back of this Flange, etc.)
2, An explanation of what this assembly is intended to do and how.

Sometimes its possible to do all the right things and still get bad results

 

[mk3223]

If the weld metal over the flange surface, it can be a potential leaking issue of the flange joint. It's a bad workmanship.

 

[XL83NL]

You probably use Cl. 600 for a reason, i.e. pressure. I don’t see how this surface would make for a leak free joint (no flange is leak free, but you get me), at ‘Cl. 600’ pressures. This modified B16.5 flange design can be made compliant to B31.3, but we need more pictures. Seems you have like some sort of instrument inserted using a flange joint. Nothing new. But that sealing surface seems like a big no-go. But again, more background and pictures.

 

[Mateeng]

You have to use a reducing flange.
Please refer to B16.5 and search for reducing flange. There you can find criteria for reducing flanges even using blind flanges to make reducing flanges. Some weld size and strength calculation may needed.
It will give you an idea to use the standard (B16.5) for your purpose. For sealing surface you will need minimum gasket surface as specified in for standard size flange. However make sure the weld does not cause any distortion of gasket seat surface.

 

[LittleInch]

Weld metal on the flange sealing surface is not allowed as this reduces the area of the gasket sealung and could interfere with the other flange face meaning lack of pressure on the gasket.

Why didn't you use a blind flange? An RF WN for this purpose is the wrong choice and results in the mess you see now.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[KevinNZ]

You could use a custom gasket with a thinner width to fit the reduced sealing face width. But this will put more compression stress on the gasket, calculations are required to check the gasket material.