Detailed information about Inconel 718 and high nickel alloys

I am working on a possible design for a component. I have to be very vague given the nature of the assembly but I have a few questions, I was really hoping to get some insight from those out there that may have experience with the material specifically.

The part I am working on designing must endure a high heat application, I need it to have very predictable behavior related to thermal expansion, and I need it to be capable of maintaining the strength over time as well as resist any oxidation that will normally plague other materials. At this point I am looking at three different materials, Inconel 718, Waspaloy, and Hastelloy X. All three seem to exhibit the mechanical and chemical properties that I need, but I will need this material to also serve as a bearing surface. The bearing is not decided on either at this point, I was hoping that the material can help drive the bearing selection. I would be using either a babbitt style bearing, or a needle roller bearing. Will Inconel 718, Hastelloy, or Waspaloy finish to adequate surface finishes for a bearing finish, and the most important part is it achievable with standard practices (ground, lapped, polished, burnished,etc) I am looking for some real world "I have done that in the past" input. As always a big thanks for the info.

we make a valve body from 718. The main bore gets chromed and honed. That should do what you want.

must endure a high heat application

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babbitt style bearing

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Probably useful to know that even the best Babbitt alloys MELT at around 900F

Also probably useful to know that 718 exists in two forms - Solution Annealed and Heat Treated - which is exceedingly difficult to machine

Sorry, I didn't realize that I typed over a part of the sentence. I was looking at possibly using a babbitt style bearing as in bearing halves, not babbitt itself. The bearings shouldn't see very high heat, the part itself will utilize internal cooling to maintain temperature. From what I have been able to calculate considering the thermal conductivity, the bearing surface will never get above 180°F. Larry good call on the hard chrome, I am going to look into it more and see if it would provide any help.

Can't answer most of your questions but I have machined Waspaloy as molds for Corningware. Not a fun material to mill, particularly with HSS draft cutters.

You ever think of using a Torrington needle bearing with an inner sleeve? That'll solve your finish questions / problems and should run OK at 180 deg

Gregg, the dimensions of the part are irregular and would prevent me from slipping the bearing over the length of the part. There are multiple locations along the part length that would require bearings.

You need to define "high heat". What lubrication will be available for your bearing? What is the surface speed of the bearing? Are there any other oxidizers or environmental difficulties besides high temperature air? What sort of strengths does the part need to maintain? What are the consequences of failure? Is regular maintenance possible?