Inconel 718 warped

Good Morning Guys,

New to this site but have read bunch of your threads and would really appreciate any insight on this problem I'm having. Material is Inconel 718, 98" Long 5-1/4"OD 4.000" ID. Sent material out to get ID gun drilled and honed to 4.000" +.002-.000 before turning OD true. Material has come back to my shop bent. Looks like there is about 1/8" belly in the middle of part. Need to turn OD down to 5.000" +-.015" with a .003" T.I.R. I need suggestions on how to get OD and ID to run concentric being that the material is bent and the OD Isn't running true with the ID. Please Help!!!!!!

Outch feel your pain.

I have never done Inconel that long before. I have done my fair share of it but it's not nice material. This is the way I think when machining it.

It has all kinds of stresses in it, and when material gets peeled off or drilled, it reduces or takes off some of the stresses and it moves around. The way I approach Inconel is to get it close to the sizes and just take off what you need to at the end both OD and ID.

So I rough OD oversize a hundred thou. Send out for rough drilling. Bend if required. Finish OD to size. Hone.

Sometimes you can bend it into tolerance. Customers of this material quite often have an acceptable bent levels. And may have come across with these problems and solutions that are acceptable to them.

Wish you luck.