ADVICE: For Mechanical Testing is the Flanges suitable for the Pipe given from the Client?

[Curious_92]

Dear All,

We have made a Proposed Welding Specification for Pipe for Fittings(pWPS) and inorder to qualify that we will be conducting the PQT. With regards to that please note the following points:
[highlight #000000]

GENERAL DATA[/highlight]

1. The Pipes are Provided from the Client. The Specs of the Pipes are as follows:
-> PSL2 BN 6" (T.S- 480.00 Y.S - 330.00)
-> PSL2 114.3*11.3MM Thck (T.S- 522.00 Y.S - 417.00)
-> PSL2 168.3*12.7MM Thck (T.S- 653.00 Y.S - 541.00)

2. Now to conduct the Procedure qualification test (PQR) we did procure the Flanges as the scope of Flanges is not covered under our
client.The Specs of the Flanges that we procured are as follows:

-> A105N 6" WN 1500# RF SCH: 120 (T.S- 546.30 Y.S - 294.30)
-> A105N 4" WN 1500# RF SCH: 120 (T.S- 508.00 Y.S - 311.00)
-> A105N 6" WN 1500# RF SCH: 120 (Machined to Thickness: 12.7mm) (T.S- 294.30 Y.S - 546.30)

3. The Tensile Strength (T.S) and Yeild Strength (Y.S) of the Pipes (that we received) & Flanges (that we Procured) are mentioned in Point - 01 & 02.

[highlight #000000]QUESTION[/highlight]

Please Do advice that as the Tensile Strength and the yeild strength of the Flnge is less than that of the Pipes's Tensile Strength and the yeild strength, will the specimen will fail under Mechanical Testing?

Or can we proceed with the Flanges that we purchased?

Appreciate your valuable feedback on the same.


Thanks you,

Regards..!

 

[mk3223]

I believed it's the typically material selection of the piping system as you mentioned. The testing is based on the flange rating which is the weakest part of the whole piping system. Of cause, you need to confirm with the Client that the flange rating of Class 1500# is suitable for the process design condition.

 

[LittleInch]

It all depends on the thickness of your pipes and what yield strength they are.

It looks to me like you have high grade pipe and low grade WN flanges. This is not a good mix.

You need to see what the equivalent thickness and %SMYS is if your pipes were made of the same material as the flanges, because at the welding point that's what they are.

You risk the flanges failing under testing as the material is weaker.

You really need to go back to the designer,

At that size though you're probably Ok as the thickness of the pipe seems to be much higher than it needs to be for pressure alone. Just don't try the same trick for 16" or 24" pipes.

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