Ading of Inco 718
Ading of Inco 718
(OP)
I would like to know the concern of double aging Inco 718. Basically, our aging cycle is 1325 8hrs, cool in furnace at 100 degrees per hour until 1150, then hold 8 hours with an air cool. Basically, our furnace chart got stuck and I have no objective evidence that the cycle was fulfilled. According to NADCAP concerns, I need objective evidence. Will it hurt to go thru the aging cycle again. Is there a risk of over aging?
Thank you!
Thank you!





RE: Ading of Inco 718
At what point did you loose the chart?
I can't find a reference, but I recall that re-agin 718 is not a good idea.
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RE: Ading of Inco 718
RE: Ading of Inco 718
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RE: Ading of Inco 718
RE: Ading of Inco 718
RE: Ading of Inco 718
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Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Ading of Inco 718
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RE: Ading of Inco 718
Is this machining bar, forging stock, sheet, etc.? What specifications are you working to, and what are the grain size requirements? Did you solution this material, or did you order it in the solution annealed condition, and what was the solution temperature?
The ideal fix would be to re-solution below delta solvus but above the gamma-double-prime/gamma-prime solvus, then age using the conventional heat treatment you used before. There is still a chance you will have some grain growth.
If you can get back to me with some answers to the questions above, particularly regarding what specifications you're working to, I might be able to shed some more light on this.
RE: Ading of Inco 718
RE: Ading of Inco 718
First off, I have to ask why no one realized the furnace chart wasn't moving. This is ~20 hour aging cycle, and from what you stated, the problem occurred early on, which begs the question that nobody looked at the equipment for 20 hours??
Second, you should have documented procedures that take certain situations into account. In this event, there should at the very least be some sort of documentation stating that there was an equipment (recorder) failure. A "deviation" or "variance" form would be filled out in this case.
Depending on your end user(s) you may be able to notify them that there was a deviation from your standard practice (with the applicable documentation), and if the parts meet all the testing requirements, you might be able to ask for some sort of relief from the record retention requirements in this particular case.
Since you are working with superalloy, and certifying to AMS specs, I imagine you're making parts for the aviation industry, in which case, is there any way to divert or specify to non-critical application? Ask yourself, would you want to fly on a plane that these parts are going into? If it were some other company's parts in a similar situation, would you trust their word and fly on a plane their parts went into?
If you do extensive enough testing, and prove that your parts meet or exceed properties of correctly heat treated parts, and have all the necessary documentation to back it up, you might be alright. Talk to the QA person that deals with the NADCAP auditors (unless you're it), and find out what their thoughts are.
Worst case scenario, re-solution, re-work to smaller size (if possible), and re-age, and make sure your recorder is working. Or don't take the chance and scrap it.
RE: Ading of Inco 718
RE: Ading of Inco 718
RE: Ading of Inco 718