I agree, the formula should be based on the radius of the curve of the head, not the before and after diameters of the plate. I checked with Compress and they still use the 3rd formula in Table 6.1. instead of the first one which is the same as UG-79.
The extreme fiber elongation limit will...
You should mention where exactly strain measurement is required and how do you measure the strain. I have reviewed hundreds of inspection and tests plans of fabricators and strains are not measured directly. Only the shape, radius, and thickness are measured after forming. The strain is...
Are you consistently operating at 850°C or just occasionally? You can still operate some materials at that temperature if just in short durations but will have to consider creep damage. Or you can just apply a refractory lining to isolate the metal to the high temperatures which is what is...
The radius you use in the formula in Table UG-79-1 or Table 6.1 for an ellipsoidal head is the mean radius of the knuckle (Rf), not the radius of the head measured in the straight flange or cylindrical part (Dm/2). The radius you use in the formula for a spherical head would be the mean radius...
Both NACE MR0103 Sec. 16.2 and NACE MR0175 Part A.2.2.4 specifically require it only for "exposed to sour service" bolting which are "denied direct atmospheric exposure". If your specs refer to NACE, then you can take that exception if the flange bolting is not insulated. Client specs like Shell...
Is your flange insulated? Cold service? Is it high severity wet H2S service? Maybe you still can use Gr. B7 if it is an external bolting with unrestricted air circulation.
Some Owners will still require basic requirements on the base metal (e.g. Max CE/C/S/V+Nb, UT Lamination Check, Normalized Condition, Hardness Limits per NACE MR0175, etc.) even with weld overlay or cladding applied. But other requirements such as PWHT, WFMT, HIC Testing, etc. can be excluded...
You have no information on my background and experience. Better be professional on this forum.
I helped by disputing your claim that you failed to justify technically. No one uses vernier calipers during fabrication and on-site for flanges. We've used UT measurements alongside hydraulic...
Who uses vernier caliper to measure elongation of the bolt? Ultrasonic measurement is typically used, but for large bolting only.
No, testing is not more demanding during manufacturing compared to the Site. They are both subjected to the same requirements.
No, only target stress or torque...
Set-on nozzles typically have additional NDE requirement from Owners where you have to ensure there is no lamination or defects on the parent base metal beneath the set-on nozzle. See 4.7.1.2. and 4.7.1.3. of IOGP S-619.
I don't see any difference in the calculations or SIF if your weld is integral (full penetration) and dimensions are essentially the same. If you also performed lamination check beneath the set-on nozzle and it is acceptable, then no strength reduction there.
I've seen them used on 150# flanges with expanded graphite gasket. But, if you have higher rating, I doubt that you can prove they can seal the flange with 500 microns of coating and that much compression experienced by the coating and gasket. What kind of coating are you using by the way?
Have you kept the radial distance between the bolt circle and the gasket load reaction diameter to a minimum? And probably use more bolts (and smaller size) to keep that further closer to reduce that moment arm.
@IdanPV, thanks for the detail. Not really sure of the specifics of ASME IX regarding that, my only concern if you would really be able to achieve full penetration with a square joint and 2mm gap that is 5mm deep. A bevel would usually be applied for better access to the root of the weld.
What is the gap between the shell and nozzle? Does the gap meet the requirement for the welding process you are using? How are you going to fit-up the nozzle? Are you meeting are the parameters in your WPS/PQR?
