4340 vs A106 machining stability
4340 vs A106 machining stability
(OP)
We have the choice of machining a 60 inch diameter ring from a 4340 or A106 forged ring.
The forging house will deliver the ring stress relieved and normalized.
The ring will be cut into 6 identical segments after machining.
We are considering a second thermal stress relief after rough machining to reduce ( eliminate!) distortion/spring after cutting.
Is either material likely to offer better stability to reduce distortion after cutting?
Thanks,
Dan T
The forging house will deliver the ring stress relieved and normalized.
The ring will be cut into 6 identical segments after machining.
We are considering a second thermal stress relief after rough machining to reduce ( eliminate!) distortion/spring after cutting.
Is either material likely to offer better stability to reduce distortion after cutting?
Thanks,
Dan T





RE: 4340 vs A106 machining stability
If you are that concerned you might add another one mid way through the roughing.
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P.E. Metallurgy, Plymouth Tube
RE: 4340 vs A106 machining stability
The A106, on the other hand, will transform much more evenly, at higher temperatures, and you can expect quite a bit of stress relieving to occur after transformation. It still may move after machining, but I wouldn't expect as much as the 4340.
Stress relieving after normalizing would make the difference less, but I would still expect the 4340 to move more than the A106. If you stress relive after machining, you may get some movement during the SR, so the best shot would be a SR after normalizing.
RE: 4340 vs A106 machining stability
How much are you taking off of the original 60 inch dia ring - inside and outside?
RE: 4340 vs A106 machining stability
The most obvious consideration between 4340 and A106 is raw material cost. If the mechanical properties of A106 are acceptable for your application, then why would you consider using far more expensive 4340?