Upgrading Inconel 625 grade 1 5

[XL83NL]

We had the need to buy Inconel 625 for a project we're doing. We ended buying grade 1, since grade 2 just wasnt available in the product form we required (tubing). Upon review of ASME SB444 for UNS N06625, would it be possible to upgrade a 'batch grade 1 tubing' to grade 2 by doing a solution anneal @ ~ 2100°F? Our application runs at 700-750 °C.

 

[XL83NL]

projects simply have a limited time in which everything needs to be engineered, procured and assembled. Not finding any mill in the (western) EU then gives you no option. Bear in mind we can’t afford a mill run as we only need about 6 metres. Add to that the differences in cross country aspects (EU vs USA markets are way different). And you’ll find such arguments don’t hold, Ed.

 

[moltenmetal]

EdStainless: if you're buying mill run quantities, the world's your oyster. If you're buying a couple lengths of tubing as my friend XL83NL is, you are a beggar and hence cannot be a chooser!

Welcome to the world we live in, Ed.

We'd be happy to have direct access to your stockroom- you probably have an off-cuts pile people like us could put into productive use...regrettably, we both almost certainly have to deal with distributors, who won't even bother to call a mill like yours for less than a mill run- and have no interest in keeping anything on their shelves unless it moves in volume.

 

[EdStainless]

And designing in an unavailable material is not an issue for you?
But seriously I understand the issues around this.
We make small runs of tubing, sometimes less than 500' on a frequent basis.
We also will re-process our material (but not other peoples) for special cases.
The real issue in not with specs like this (that use the same raw material) but in cases where we would need to buy 5T of raw material in order to even start. Or cases where RM has a 16 wk lead time.

You can have it quickly, inexpensive, or correct; select any two of them.


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P.E. Metallurgy, Plymouth Tube

 

[moltenmetal]

We often need to have tubing re-drawn for us- and sometimes to have pipe re-drawn into tubing, and even on occasion, to gun-drill barstock to make a short piece of "pipe". But even those strategies are of little help when what you really need is one or two 20' random lengths.

Engineering is the art of the possible. We usually work not with the ideal material, but with the material we can actually buy that best suits the project's needs. In our business we work comfortably within these restraints all the time, because we're not building units with 30+ yr design life. But sometimes, when the choice is between the right but impractical to obtain material (i.e. having 500 ft made so we can use 20) and an available material that represents a safety risk if/when it fails and where said failure can't be prevented by monitoring etc., the solution is to not proceed with the project.

 

[WKTaylor]

OK, guys, I have to ask, again...

IF Your need is for a standard tube Dia and wall thickness [and/or 'close-enough', see attached Dia X WT table], in short lengths like this, then why not consider aerospace quality SAE AMS5581 hydraulic quality tubing from a reputable materials supplier?

http://files.engineering.com/getfil...789&file=Aerospace_Tubing_Stndrd_Dia_X_WT.pdf

Regards, Wil Taylor

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[XL83NL]

ASME code requires ASME material, not SAE. Not sure if that SAE grade would even pose an improvement wrt availability & sourcing.

 

[EdStainless]

While AMS5581 has the same chemistry limits and min strength as SB444 there is no way to tell if it was annealed hot enough for the Gr2 requirements.
Most mills have a different process for the AMS material. Using an lower anneal temp results in less load on the furnace and less distortion of the tubing, so most people will anneal no hotter than they need to.

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P.E. Metallurgy, Plymouth Tube

 

[Sparweb]

...ASME code requires ASME material, not SAE...

Forgive me - I don't mean to get you sidetracked, but... Specsmanship?

Like WKTaylor, I'm a little surprised by this. Given the "art of the possible" we try to practice, as Moltenmetal puts it, it never occurred to me that a code could be written to specify not only the minimum properties, but prevent use of materials with greater strength, temp range and creep resistance, too. I do not have such hand-cuffs in my industry. SAE-AMS spec also includes quality inspection and testing so I don't see where it falls down... except if you assume a turf war?


STF

 

[metengr]

Where did this come from?????

but prevent use of materials with greater strength, temp range and creep resistance,

ASME Boiler and Pressure Vessel Codes and Standards are all about boiler and pressure vessel safety with longevity using design by rule or design by analysis. As such, materials are specified with minimum strength and ductility properties only to ensure the materials can handle expected processing and material that has mechanical properties higher than minimum is great except you don't take credit for it in design by rule.

You also have the option of design by analysis where here you have the freedom to take advantage of higher strength materials using analysis that demonstrates similar safety as design by rule. Service temperature limits are another issue and are dictated for a reason, to avoid premature failure from time dependent failure mechanisms.

 

[Sparweb]

...freedom to take advantage of higher strength materials ...

But only if they are stamped with ASME specifications?

STF

 

[metengr]

Correct. Again, the boiler and pressure vessel industry is about long term, safe operation. However, one does have the option of submitting code case for consideration of non-ASME materials.

 

[EdStainless]

The limits for this alloy, and the reason for Gr1 and Gr2 depend on the anneal temp and if you dissolve the stabilizing carbides or not. While the choice of anneal changes the tensile strength, the RT tensile alone is not enough to know which elevated temp tensile and creep properties you will have. You need to know the anneal temp to know that.

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P.E. Metallurgy, Plymouth Tube