Does anyone have any idea about how to calculate or find the temperature at which a 4140's metallergy becomes effected. What we are trying to do is cut out a sleeve that as been threaded into another sleeve w/o severely effecting the outer sleeve from the heat or heating the entire part via induction heating and then removing the inner sleeve by chilling it to break the threads loose. The outer sleeve will be mag particled to check for damage aftewards but Im wanting this to work on the first or second try. The entire part (both sleeves are 4140 alloy).Im sure Im being as clear as mud................ Any ideas?
If the part You want to save was heat treated, You don't want to excede the temperature it was tempered at. You would probably be safe staying below 500f, but that is only a guess without knowing how hard the part is now.
Ideally you could check the hardness and cross referance the tempering temperature. Most likely with comerical heat treated 4140 you can get real colse to 1ooo'F before you need to worry. Really hard stuff is tempered below 1000.
Ron, Thats kind of what I was thinking but, we are going to mag particle the part afterwards to see the effects. Hopefully all goes well. I wil post what we end up with. Thanks to you and Dave
Ideally you could check the hardness and cross referance the tempering temperature. 
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