thermal expansion distortion..

[mfgenggear]

The Parts.. AISI 9310 ring gears , Internal gear carburized, with an Internal spline not carburized.
process ~ carburize gear IAW AMS 2759/7 .027-.032 case depth. diameter ~ 4.321 diameter 18 DP 20Deg. PA
I can not show a pic of the part, it is proprietary

Issue : rings expanded .010 from original size..

My guess: the parts transformation from Ms to Mf was to fast by using a fast to normal quenching oil..?????

I am stumped on this one fellas never had this happen on quench plug, only with gleason expanding dies which were
expanded to far.

any suggestions of why thermally these parts open up .010.

 

[Compositepro]

When you slowly heat a ring, it expands slowly and uniformly, with low temperature gradients. When you quench a ring quickly you will have very large temperature differences between the surface and interior of the ring. The cold surface contracts while the hot interior does not. This causes internal stresses in the ring, which can exceed the yield strength of the metal. This results in permanent dimensional changes.

 

[mfgenggear]

Hi Compositepro

so basically it is possibility that the quench temperature and speed could have attributed to expansion of the parts.
due to outside surfaces cooling faster than the internal surfaces.

for got to add the parts where Normalized , Harden and Tempered after rough turn.