How do I verify A240-321 sheet is in Solution Annealed Condition?

[ProjectEng99]

Currently we use test ASTM A262 Practice A. Problem: It takes 10 days and it often fails. I want a faster test.

Details:
We buy .016" thk A240-321 sheet. It comes certified from the mill as solution annealed. However, to get .016" thk, a Rerolling company usually Rerolls a thicker sheet down to .016" which adds cold work....so it's not in a solution annealed condition anymore. To verify it is still solution annealed we do an A262 Practice A test but it takes 10 days and the material often fails. Practice E is only 24hrs but does not give an indication of sigma which is important for 321 since it’s stabilized. We perform the chemical & physical tests required per A240-321, but I'm told that those tests do not confirm that mat'l is in sln Annealed condition.
Thank you,
Dee Anderson

 

[Goahead]

I am not sure I understand the problem fully.
If a Rerolling company performs cold rolling on the material, as you rightly suggested it is not anymore annealed. Per your requirements, it should be resolution annealed with documented heat treatment.

How could it possibly be still solution annealed?

If you wish to check the material ductility, bending could be a useful test. If a material specimen, with its long dimension tranversal to the direction of rolling, can be bent on itself with radius zero without cracking it is considered fully annealed.

If a correlation could be established between this test (or with the minimum radius achievable) and all those other tests required by specification, it might help to provide a rapid qualitative screening test pending the results of the other tests.

http://www.welding-advisers.com/

 

[EdStainless]

Practice A only takes an hour or so, it is just a micro.
And why would rerolling cause it to fail??
Do you know that the material would pass prior to rerolling?

If the material still meets the ductility (elongation) then a mill would probably consider it annealed.


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Corrosion never sleeps, but it can be managed.

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[unclesyd]

A ductility test would only have bearing on the formability and give some indication of the physical condition of the material.

The fully annealed condition could be called out for both corrosion resistance and/or ductility.

Probably in this case ductility is the prime consideration and ductility testing is a viable check.

 

[ProjectEng99]

Today I found out that rerollers DO perform a heat treat, and that Nitrogen pick up during anneal at reroller MAY be causing corrosion test A262 practice A failure. Nitrogen is not reported for A240-321. Another Ni source is from the mill. This particular mat'l is from a Finland mill and I'm told that mills across the pond often add more Ni than US mills.

New questions
1. Would Nitrogen cause failure of corr test A262A?
2. Is add'l Ni from over the Atlantic mills common?
3. Is there a common error during annealing that would cause failure of corrosion test A262A?

Answers to posed questions:
a. We do not know if mat'l would pass prior to rerolling.
b. Thank you, but a ductility test wouldn't help. Material passes it's chemical & physical tests (including elongation) required per A240-321 but does not pass A262 Practice A.

This has been a recurring problem for us and I appreciate your time. Thank you all.
Dee Anderson

 

[EdStainless]

Uptake of N during anneal will make samples look like they have grain bound. carbides, when it is actually nitrides. I have seen Practice E coupons develop texture when bent becuase of this.
Nitrogen is not required to be reported, even if it is deliberately added. Nitrogen in solution should not have any impact on your situation. Extra Nitrogen absorbed during anneal will be very preferntial along the GBs.
Is the strip actually sensitized when you get it? Run some samples prior to your sensitization treatment and see what you get.
There is also an Electrochemical version of the test, G108, that gives a quantitative result.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[ProjectEng99]

No it is not sensitized when we get it. What would running a test on non-sensitized tell us?

We are considering G108. Thank you.

 

[EdStainless]

There may be various surface/microstructural conditions that are making it difficult to test. If you ran samples in the 'as recieved' condition then those would be your baseline. If they show ditiching or fissuring then you have other issues.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm