ASTM A479 UNS31803 V NORSOK M630 D47

[shebelaw]

Interms of 'quality' of material what's the difference between a bar according to ASTM A479 or the NORSOK standard.
Am I correct in assuming that according to ASTM A479 there is no requirement to do charpy V-notch test on the material. what are the acceptance criteria for the corrosion test/metallographic examinations

 

[Danlap]

Hi,

Not really sure whether your question is regarding general pressure containing parts (vessel,piping, etc.) or just valve (aside from Safety Relief valve).
one ASTM standard generally should be complemented with other ASTM standards.
Charpy test requirement is in accordance with ASTM A370. Best practice is whenever the minimum design temperature is below -20/-29/-50 degree Celcius (some companies refer to different standard) should always be Charpy tested (x,y,z orientation).
This method is to determine whether the mechanical properties of the end product will remain the same (within tolerance) as the one prescribed on its designated ASTM.

The bigger concern with valves made from bar stock can result in a leak path along elongated inclusions. This may not be detected during hydrotest as it takes a while for the inclusions to corrode and permit leakage.
Therefor, ASTM A479 provide supplement A292. In a more detail extend (valve) ASTM A961 (S50.1)had similar supplement which is ASTM E381.

The method is described clearly on A292. Analytical parameters of ditches, micro-pitting examination among (micro)grains are defined there. Among other criteria of course.

I don't encompass NORSOK standard. However the general understanding is that steel manufacturer which complies with NORSOK have endorsed similar measurement method as part of their quality control. Which underlined as most of them would be European steel fabricator and small numbers of Asian's manufacturers. This is the opinion that I commonly interfaced.

Maybe others have different view.
PS: Sample of macro-etch analysis is the same batch as the final product.

Regards,
MR

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

 

[shebelaw]

Okay, i see now that I am probably in the wrong thread I was referring generally to pressure piping. but you have managed to answer my doubts about the use of ASTM A479 alone to order raw material for my product.
thank you

 

[SJones]

Since the NORSOK standard is supplementary to the ASTM standard, then it must be deemed more rigorous. It's certainly much more clear in terms of required tests and the associated acceptance criteria. Whether more testing translates to more 'quality,' only the user of the material can say. You might want to look at publications such as API TR 938-C, or EEMUA 218.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.