Raw material used for flanges

[Silambarasan]

Hi,
We had purchased flanges(SA182 F316L) from a vendor, while reviewing their test certificate i came across the 'raw material used' column which says SS Round bar.
ASME Section VIII Div.1 UG-14 says 'Except for flanges of all types, hollow cylindrically shaped parts may be machined from rods & bars. Similarly Section II-A SA182 Para 6.4.1 & Section II-A SA961 para 6.1.1 says Flanges of any type, elbows, return bend shall not be machined directly from rods & bars.
Since the flange is for manufacturing a pressure vessel with 'U' stamp, whether we have to replace it.
Can anyone please advice whether my interpretation is right?

Thanks & Regards
M.V.Silambarasan
+919591507348

 

[moltenmetal]

I stand to be corrected, but I believe that in ASME VIII you are permitted to make flanges of limited size from slices of round bar IF, and only if: a) the material has been UT examined prior to machining and found to be free of flaws and b) radial and axial tensile tests have been done on the source material and found to meet the spec. The concern would appear to be radial lamination-type flaws in the round bar, akin to the laminar flaws which might be found in plate. If I recall correctly, there is a similar rule related to using plate to make hubbed flanges, where a lamination type flaw might cause the hub to fail.

For stainless steel, in my opinion, this is a bit of a silly rule in the size range where using round bar to make flanges is at all practical. I've never seen a defect in a piece of austenitic stainless steel forged round bar (rather than a "round bar" made by casting) which would render a flange constructed from a slice of that material unsafe. The requirement to forge small flanges in near net shape (ie. including piercing the central hole) would therefore seem to be overkill. In carbon steels, however, radial flaws might be more common.

 

[marty007]

SA-182 states:

6.4.1: Flanges of any type, elbows, return bends, tees, and header tees shall not be machined directly from bar stock.

Cheers,

 

[SnTMan]

What kind of flange is this? Standard or custom? Large or small?

Stainless round bar is often dual certified as forging, maybe you need to get a copy of the original MTR from your vendor.

Regards,

Mike

 

[Silambarasan]

Hi SnTMan,
We had purchased two different sizes of flange, one is 2" WNRF 300# & another special type flange as per end user's requirement of OD230 36mm thk.
i'm unaware about the flange manufacturing process, SA182 Para6.4.1 states 'shall not be machined directly from bar' which means you can forge the round bar after that you can machined it to attain the proper state. Is my interpretation is right???

Regards
M.V.Silambarasan

 

[moltenmetal]

I was referring to an ASME VIII appendix 2 flange, not a B16.5 flange.

 

[SnTMan]

Silambarasan, I would assume, if machined from solid, round forging your flange is acceptable.

Regards,

Mike

 

[Silambarasan]

Hi Mike,
Me too assuming the same, Thanks for your information

Regards
M.V.Silambarasan