Machining Inconel 718 Per AMS 5962 (Cold Reduced) 6

[FastenerDude]

I have a customer who wants me to make a double end stud out of Inconel 718 per AMS 5962 (Capable of 220 KSI Tensile). The stud size is a 1-1/4" diameter (with an unthreaded body diameter of 1.111"). The only material I can get is 1-3/4" round. I raised the concern to my customer that machining off that much material may remove the cold work that was applied to the bar. My customer is saying that isn't true. Am I correct in my thinking that turning off that much material will remove most of the cold work?


Greg
System 22, Inc.

 

[WKTaylor]

FastenerDude...

Something about Your initial statement bothered me. After re-reading the spec a couple of times... and digging into another design document I just happened to root-out [very recently revised I might-add]... it finally hit me between the eyes and the light-bulb went full bright.

"... The only material I can get is 1-3/4" round. ..."

Per AMS5962A

para 1.1 Form...

This specification covers a corrosion and heat resistant work strengthened nickel alloy in the form of bars and wire, 1-1/2-inches (38-mm) and under in nominal diameter (see 8.2).

Per this paragraph, 1-3/4-inch Dia Bar exceeds spec maximum [1-1/2-inch Dia] and is NOT permitted.

NOTE.
I must freely admit that I could not find a copy of AMS5962 [original release, 1997]. That spec-version MIGHT have allowed larger diameter bar stock... or just maybe... max permitted diameter was just omitted or was actually larger. However, in the AMS5962A copy I have access-to [Rev A 2003, re-affirmed in 2010] there was NO indication para 1.1 had been revised. Since 2003 is a distant memory, though, I generally 'presume' the material purchased should conform with Rev A.

CAUTION.
The hair on the back of my neck is standing-up. I am concerned that You were sold this 'certified(?) material' when it clearly exceeds spec maximum allowed diameter. Exception: There are rare-times when a vendor will make a special one-off production run of oversized material for customer specific sale; with the full understanding that "X" [or "Y", or "Z"] is non-conforming to a spec limit or value... but this clearly stated on the "certs".


Regards, Wil Taylor

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