Ring Flange with plate material ? 1

[401laurent]

Dear All,
I'm designing a 20in Dia. flanged manhole as per Appendix 2 ( ring type loose Flange + flanged Dished cover) see attached (2) sketches , and I have some confusion about material flange specification , so my question is very simple:
as theses flanged are not hubbed flanges, nor reverse flange, so Can I use a plate materail (SA-240-304 for example) for theses ring flanges?
is it mandatory to use Forging material?

Thanks.
Laurent.

 

[401laurent]

Sorry,
please find the attached second sketch for the flange.
Thanks.
Laurent

 

[SnTMan]

401laurent, plate is often used for your second sketch. I don't think I have ever seen plate used for the flange on your first sketch, but I believe it is permitted.

Regards,

Mike

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

 

[r6155]

Why not standard flange and flat cover?
Regards
r6155

 

[JStephen]

I was thinking there was a requirement that a "plate flange" had to be rolled from bar- would have to check and see if that's correct or I'm remembering wrong.

 

[401laurent]

JStephen,
that is exactly what I'm worry about it, we need more help to make this point more clear,
because if I can use plate for this flange, that's means that all Slip on flange ( just without hub)can be made from plate material.
that what we need to confirm.
Thanks.
Laurent.

 

[moltenmetal]

If the flange construction is such that potential laminations in plate material are not put in tension by the action of process pressure, you're OK to use plate material to construct the flange, unless I misremember the code. So that means slip-on type body flanges (without hub) and (otherwise featureless) flat blind flange covers are fine to make from plate.

If you want to make a flange out of something other than a near net shape forging, but it does not meet the criterion above, then you need to do soundness testing (UT before machining, plus tensile tests along both primary axes), whether you use plate or a forged bar which has not been pierced.

As always, I'm too lazy to go back, find and quote you chapter and verse from the code on this, so take with an appropriate measure of salt- and I defer to those who use ASME VIII on a daily basis and have it tattooed to the back of their eyelids.

 

[SnTMan]

Appendix 2 has a bunch of rules for hubbed flanges made from plate. It has no special rules for hubless flanges made from plate. It is not prohibited, therefore it is permitted

For slip-ons, blinds and so forth, rings or rounds burned from plate are widely used. It is a good idea to examine for laminations, but really, even this is not done that often for these types. However see UG-93(d)(3).

Regards,

Mike

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

 

[JStephen]

Yes, looking just now, it is the requirement for hubbed flanges that I was remembering, not plate flanges.