×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Upgrading Inconel 625 grade 1
5

Upgrading Inconel 625 grade 1

Upgrading Inconel 625 grade 1

(OP)
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.

RE: Upgrading Inconel 625 grade 1

XL83NL;
Yes.

RE: Upgrading Inconel 625 grade 1

(OP)
Hi metengr. Thanks for your reply. Do you have any recommendations regarding holding time, heat up and cool down ramp? Will the solution annealing treatment not devaluate any other material (mechanical) properties?

RE: Upgrading Inconel 625 grade 1

The solution anneal should not adversely effect other mechanical properties. As far as hold time, for tubing depending on thickness I have seen 10 minutes as a solution anneal hold time once temperature is reached.

For ramp up and cool down rates, I would recommend you work with a reputable local heat treater or tube mill because this depends on furnace charge and type (batch versus continuous).

RE: Upgrading Inconel 625 grade 1

You do know that after the anneal you will need to straighten the tubing, and then re-do all testing, both NDT and mechanical properties.
This is very odd, any mill that makes this could have simply altered the final anneal and give you the correct material.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Upgrading Inconel 625 grade 1

XL83NL...

Did You procure Your tubing per ASTM B444? NOTE: I Could NOT ID any similar tubing spec per ASME

This may/may-not be useful...

SAE AMS5581 Nickel Alloy, Corrosion and Heat-Resistant, Seamless or Welded Tubing 62Ni - 21.5Cr - 9.0Mo - 3.7Cb (Nb) Annealed (Composition similar to UNS N06625)

Per the AMS spec...

1.2 Application
This tubing has been used typically for fluid lines requiring high strength and corrosion resistance at temperatures from cryogenic to 1800 °F (982 °C), but usage is not limited to such applications.

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Upgrading Inconel 625 grade 1

Quote:

NOTE: I Could NOT ID any similar tubing spec per ASME
?????

See ASME SB 444

SPECIFICATION FOR NICKEL-CHROMIUMMOLYBDENUM-
COLUMBIUM ALLOYS (UNS N06625
AND UNS N06852) AND NICKEL-CHROMIUMMOLYBDENUM-
SILICON ALLOY (UNS N06219) PIPE
AND TUBE SB-444

ASTM does not provide process details, it is expected that Manufacturer's know this and it is up to the Purchaser to trust BUT VERIFY!!!!!!!!!!!!!!!!!!!!!

RE: Upgrading Inconel 625 grade 1

Just be careful given that the anneal can result in a lot of scale...it would need to be annealed in hydrogen to keep it "bright". Not sure if that affects the properties at all.

RE: Upgrading Inconel 625 grade 1

In production this tubing is annealed in dry high purity hydrogen (D.P.<-50C and O2<1ppm) to preserve the surface finish.
The only difference between Gr1 and Gr2 is that Gr2 is annealed at a higher temp and therefore has lower strength.
We make both of these all of the time (as do our competitors), but the chances are that distributors will have limited options.
Why do you need Gr2? It is not stabilized since it has been solution annealed.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Upgrading Inconel 625 grade 1

Dohhhh... I've got-it... bad aerospace engineer...shadessad

ASME BPVC.II.B-2017 ASME Boiler and Pressure Vessel Code - An International Code

SB-444
SPECIFICATION FOR NICKEL-CHROMIUM-MOLYBDENUM-COLUMBIUM ALLOYS (UNS N06625 AND UNS N06852) AND NICKEL-CHROMIUM-MOLYBDENUM-SILICON ALLOY (UNS N06219) PIPE AND TUBE
SB-444

(Identical with ASTM Specification B444-06(R11) except that certification and test report have been made mandatory per SB-829.)

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Upgrading Inconel 625 grade 1

(OP)
Thanks all. Good remark on the bright annealing. Starting to get 2nd thoughts now if the bright annealing will bring me so much extra as compared to the potential disadvantages of not doing it.

Quote (EdStainless)

Why do you need Gr2? It is not stabilized since it has been solution annealed.
Our service temperature is 700-750 °C. Grade is only allowed to 649°C as per Code. Also review section 1.1.1 of B444, which details the use of grade 2. Hence grade 2 is required.

RE: Upgrading Inconel 625 grade 1

(OP)
PS; we'll use the tube for compression fit twin-ferruled fittings, so hardness (after annealing) is also an issue.

Quote (EdStainless)

.. any mill that makes this could have simply altered the final anneal and give you the correct material.
Well, in the EU, it wasnt easy (better yet almost impossible) to find 625 grade 2 from a mill that usually provides quality.

RE: Upgrading Inconel 625 grade 1

XL83NL
What did you do finally?

RE: Upgrading Inconel 625 grade 1

(OP)
Use grade 2. No Heat treatment of whatever method to upgrade it.

RE: Upgrading Inconel 625 grade 1

XL83NL
So how come you are using something between 700-750 C when it is only allowed up to 649 C as per code (as per your own threads)? I am curious.

RE: Upgrading Inconel 625 grade 1

If the final anneal temp wasn't high enough you can't call it Gr2, the properties are not the decider for this.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Upgrading Inconel 625 grade 1

(OP)
Operating temperature is (far) below design, so we have a big margin on that. Some of the hottest part might never even see 650 °C. What are you gonna do when you cant source what you need and there's no alternartive? A post fabrication heat treatment to 2100 F would damage the material, so that was no option. The application is a test unit which will be disassembled frequently enough to determine any material degradation.

RE: Upgrading Inconel 625 grade 1

Failure at the conditions in question is going to be related to either creep or oxidation/spalling material loss. Neither happen instantaneously. In hot equipment/piping like this, ongoing periodic inspection and replacement is the only strategy that is possible. It's not possible to just pick another, more resistant metallic material. This is what happens when people apply code thinking closed-mindedly to what inherently must be an "engineered for purpose" solution.

RE: Upgrading Inconel 625 grade 1

Well said, XL83NL.

RE: Upgrading Inconel 625 grade 1

Hire a sourcing person that can find the correct suppliers,
or learn how to place orders early enough.
Any mill that produces this product can make both grades.
Sometimes paying more and waiting longer is the correct option.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Upgrading Inconel 625 grade 1

(OP)
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.

RE: Upgrading Inconel 625 grade 1

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.

RE: Upgrading Inconel 625 grade 1

2
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.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Upgrading Inconel 625 grade 1

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.

RE: Upgrading Inconel 625 grade 1

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/getfile.aspx?folder=f...

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Upgrading Inconel 625 grade 1

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

RE: Upgrading Inconel 625 grade 1

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.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Upgrading Inconel 625 grade 1

Quote (XL83NL)

...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

RE: Upgrading Inconel 625 grade 1

Where did this come from?????

Quote:

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.

RE: Upgrading Inconel 625 grade 1

Quote:

...freedom to take advantage of higher strength materials ...
But only if they are stamped with ASME specifications?

STF

RE: Upgrading Inconel 625 grade 1

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.

RE: Upgrading Inconel 625 grade 1

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.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close