Does A350 LF2 CL1 flanges (failing low temp impact test) meet A105 flange requirements? 2

[Lan85]

Recently, I received an alert from the supplier saying that when tested for low temperature fracture toughness test, some of the flanges they supplied to us before, did not meet the requirements (required 16J min per specimen and 20J average across 3 specimens). We used these heats in one of the project. These are A350 LF2 flanges and already fabricated and constructed on site.

Furthermore, the supplier said that "although there is doubt over whether the flanges sold meet ASTM A350 impact testing requirements, they do meet all requirements of ASTM A105". When I asked if the minimum allowable temperature can be -29 deg C, they say Its beyond their capability to comment on that. Their original statement is kind of misleading.

I reviewed the temperature requirements for this project and there is no need for below -29 deg C service. I would like to know, even though A350 LF2 flanges fail low temp impact test, can the minimum allowable temperature be -29 deg C (ie same as A105, which does not require impact test)? Any guidance on this would be appreciated.

 

[BigInch]

If the flange passes A105 criteria, it is an A105 flange. This may be more of a paperwork problem than anything else. You should ensure that you are satisfied that the flange has sufficient toughness for your minimum operating temperature one way or another, regardless of if A105 requires impact testing or not. Generally I'd say, if you ordered A105, you're OK. If you managed to order an A350 flange, you're not meeting spec, so that will be a QA verification nightmare. Send it back now and avoid a more costly replacement later.


Independent events are seldomly independent.

 

[SNORGY]

What was the supplier's motivation to impose impact testing on flanges that were already qualified (presumably) to A-350-LF2-Class 1? Was it just part of their QA/QC or QMP?

People have to be careful what they ask for. I once asked for HIC-qualified plate (PS-10), and a supplier found me the plate. Irrespective, we asked for a HIC test and, son of a gun, the test failed. We now had HIC-plate c/w mill certs etc. that was proven to not pass a HIC test.

Should have left well enough alone. I'm with BigInch. Maybe get some A-105 / A-105-N flanges and call it a day.

 

[Lan85]

SNORGY:
When it was purchased for the project, the flanges were already qualified for A350 LF2. It was one of supplier's client who did impact testing on the flanges and it failed. Afterwards, the client notified the supplier and supplier sent an alert notice to other clients who were supplied with same heat number flanges. Also, all these flanges are installed at the site already, commissioned and in full service.

Afterwards, the supplier did more tests. When looking at their data, even at 0 deg C, 2 out of 3 samples did not meet the criteria (below 20J).

I find it strange that A105 do not have any impact test requirements. Does it mean that even if it fails at very low impacts (say 2J) at 0 deg C, it still passes the code?

 

[SNORGY]

To my knowledge there is no requirement for impact testing A105 flanges for MDMT greater than -29 C in the B31.3 piping code.

 

[stanweld]

Lan85,
Yes. If you tested the A-105 flange and had your low impact values, it would still be A-105.

Location of the test specimen per 7.1 of SA-350 is highly important. You should never assume that all forgings represented by the test will have the same impact values. Also note 7.3, "Impact tests may be made at temperatures different from those in Table 4, provided the test temperature is at least as low as the intended service temnperature, and that the forging is suitably marked to identify the reported test temperature."