[pattonrm]

I am working with AMS 2770 and am having difficulty interpreting the number of solution re-heat treatments allowed. We typically work with clad aluminum sheetmetal thicknesses between .020" and .125". The spec states that these parts are "limited to one additional solution heat treatment in addition to any by the raw material producer". If we receive material in O condition, it has not been solution heat treated at the mill. Therefore, am I allowed to perform (2) solution heat treatments, or am I limited to (1) treatment, regardless of what happens at the mill?

This part of the spec seems very vague to me, and open to much interpretation. I am wondering what others are doing and how you may deal with rework situations (such as an interrupted solution cycle, overaged parts, or solution heat treated parts that are not formed within the allowed time after quench) and the determinination of how many re-solution treatments are allowed.

[The Heat Treat Doctor]

I have a great deal of experience working with Aluminum heat treating and on interpreting related AMS specifications (AMS 2770, AMS 2771, AMS 2750, etc.) and I would be more than happy to help out either here on line or via e-mail.

As to your specific question, you are allowed only one (1) resolution tratment on material received in the O condition. As you summarized, the specification clearly states that you are limited to only one...

I do not find the specifications vague, but then again I have worked with them for many years. They are not intended to be "open to interpretation". Respectfully, they must be read carefully and each word conveys it's intent. Rework is a serious matter and great deal of care taken so that the end result is a quality product.

Good luck,

[pattonrm]

I appreciate the response. I am still not 100% clear though.

So for material in O condition, do we get 1 solution heat treatment, or do we get 1 solution heat treatment and 1 re-solution treatment.

Since annealing is similar to solution heat treatment, except without the quench, is the annealing at the mill to O considered as one of the solution treatements?

Am I making this interpretation more comlicated that it needs to be? Is it simpler to say, regardless of what the process is at the mill, we get (O) treatments for .020" material, (1) treatement for .020"-.125" material, and (2) treatments for material greater than .125"?

[DrOrpheus]

I believe you as a heat treater are limited to solution treating it one time and one time only if supplied in the solution treated condition. Not too knowledgeable on aluminum, but with stainless alloys, that's how it is. I think they should loosen up a little on these requirements in certain situations, such as raw stock and sheet. If you get a sub par batch from the mill to be aged with tensile requirements, and they fall low or don't meet the elongation requirements, you gotta make sure you hit it on the nuts the 2nd time because there are no more solution treatments left, and some only give you one re-age along with your re-solution, which makes it more difficult.