ASTM A333 Grade 1 fracture toughness

[EdL86]

Hi guys, this is my first post here.

I'm working on a critical flaw sizing job of a pressure vessel which has A333 Gr.1 nozzles under a low temperature condition (-33 Celsius).

The client is unable to provide us with fracture toughness or Charpy test data.

As such I was using API-579 Annex F guidelines to estimate the transition region fracture toughness value, BUT it is way too low and is not yielding a realistic result.

I've had a look online and on databases, but all available data seems to be on Gr.6. Can someone point me to where I can find fracture toughness or Charpy data on Gr.1 or equivalent?

Thanks in advance!

 

[metengr]

If you review ASTM A 333, the minimum impact energy requirement for Grade 1 is 13 ft-lbs (for a set of 3 specimens) or 10 ft-lbs for one specimen. The minimum impact test temperature for Grade 1 is -50 deg F. Without having specific heats to test, I would recommend you use the most conservative approach with 10 ft-lbs min at -50 deg F.

 

[EdL86]

Hi, thanks for the response! Yup, I've reviewed it, but keeping that in mind, for the -33 deg C (-27 deg F or so) application I feel that the minimum impact energy requirements would be too conservative.

Is there any master curve or extrapolative approach that can be used for CVN values NOT at the transition temperature?

 

[metengr]

EdL86;
Here is the problem, unless you can actually test a specific heat of A 333 Gr 1 steel used for the nozzle or somone has run fracture toughness testing to provide reasonable data, there is no way you can defend your analysis with any certainty.

There are no master curves for impact properties. This is why using lower bound test data sets the ground floor for evaluation. If your results are acceptable with lower bound data, actual testing which results in higher values is a bonus.

You might try and have the client purchase SA 333 Gr 1 steel with a CE close to what you have and run CVN impact tests.