mondalloy

[gcode]

just got an RFQ for a blisk made of a "mondalloy" forging

I've never heard of it.. even google draws a near blank..

One material company who offers "mondalloy stainless steel"

I can't find any data at all.

 

I've got a feeling that it's real ugly stuff..

Has anybody heard of it??

[gcode]

OK,

I found an Air Force research paper that mentions it.

Its a "nickel based super alloy" which means it's probably VERY difficult to machine

[gcode]

Materials for Liquid Rocket Engines for the Integrated High Payoff Rocket Propulsion Technology

(IHPRPT) program:

•

 

Turbopump Housing: Nickel based super alloys for LOX. Mondalloy improved Ni based Ox

compatibility over Haynes 214.

[Newbeeee™]

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Your boss won't mind - he'll take it on. He's got an expensive okuma to pay for

[GoetzInd]

Yeah you may have to run carbide

 

Mike

[mkd]

never heard of it

 

http://www.haynesint...ynesAlloyPF.htm

75% Ni with 16% chromium

Haynes214 is basically nickel with a chunk of chromium thrown in.

maybe throw some ceramic inserts at it? high rpm light cuts?

 

couldn't be any worse than some cobalt turbine sections i did years ago

[gcode]

Your boss won't mind - he'll take it on. He's got an expensive okuma to pay for

 

This is a little baby part Ø8." x 12" , way too small for our Okuma

It needs to be held between centers. Its perfect for 5X mill turn.

We're not really set up for this part, but that doesn't mean the boss won't take it on

[Guest MTB Technical Services]

For machining purposes, treat Mondalloy like an Inconel 600 or X-750 alloy.

 

Hayes214 is an alloy used for low-stress parts in high-temp applications.

It's got a high aluminum content for oxidation resistance.

 

Mondalloy is used in high-temp applications where oxidation resistance is needed but the part stress makes Hayes214 impractical.

ie. liquid fuel rocket engines

[within a thou]

I have cut a lot of invar 36 and 42 which is a nickel based alloy (but only 36% and 42% nickel no where close to the 75% you are dealing with). I got the best results using hss corn cob roughers to cut it. The invar is very toxic to machine I would look into safety data and see what type of ventilation or respiratory protective equipment you would need to cut it.

[Guest]

I'm thiking you want to use ceramic tools everywhere you can 'em for starters.

[Thee Dragracer1951]

My experience is that it's a lot like Nitronic 60. I've used Carbide or Ceramic. It's a pain, but you'll get through it.

I just realized you're talking about a turned part.

Ceramict for sure.

[gcode]

this is a shaft with radial impeller blades milled from a disc in the middle of the part.

nearly every diameter on the part is ±.0001 and all the blades are .002 MMA.

Its part of a LOX pump and must spin crazy fast.

I took a highlighter and marked all the tolerances up and sent it back to estimating.

So far its been <crickets>

It would be a nice part for someone with the right machine, but that someone is not us

[Newbeeee™]

this is a shaft with radial impeller blades milled form a disc in the middle of the part.

nearly every diameter on the part is ±.0001 and all the blades are .002 MMA.

Its part of a LOX pump and must spin crazy fast.

I took a highlighter and marked all the tolerances up and sent it back to estimating.

So far its been <crickets>

It would be a nice part for someone with the right machine, but that someone is not us

Oooooooooooooooooooooooooooooooooooooooohhhhhhhh!!!!!

You could measure those bores 5 times and get a different measurement

 

I live by the statement of 'It's not the challenge of doing the part, it's the challenge of making money from doing the part'.

And this looks like it's wrapped up in BIG bucks!

[GoetzInd]

I live by the statement of 'It's not the challenge of doing the part, it's the challenge of making money from doing the part'.

And this looks like it's wrapped up in BIG bucks!

 

+1. We always tell our customers, it's not making it, it's making it for something youre willing to pay haha.

 

Mike

[mkd]

this is a shaft with radial impeller blades milled form a disc in the middle of the part.

nearly every diameter on the part is ±.0001 and all the blades are .002 MMA.

Its part of a LOX pump and must spin crazy fast.

I took a highlighter and marked all the tolerances up and sent it back to estimating.

So far its been <crickets>

It would be a nice part for someone with the right machine, but that someone is not us

i was wishing my mill turn was up and running right up til i read this post...

+/-.0001 eeeeeekkk

 

grind after final machining...how bad could it be?

[gcode]

I live by the statement of 'It's not the challenge of doing the part, it's the challenge of making money from doing the part'.

And this looks like it's wrapped up in BIG bucks!

 

exactly.. and the sales staff is saying.. so what if we get killed on these 3 parts

there will be a follow-on order for thousands

[Thee Dragracer1951]

exactly.. and the sales staff is saying.. so what if we get killed on these 3 parts

there will be a follow-on order for thousands

 

It's the follow ons I'd be terrified of...

[GoetzInd]

Turning that tolerance at that dia. with a stat. cap. process is gonna be next to impossible. IMO of course. Even grinding that tol. in that material can't be easy.

 

Mike

[crazy^millman]

Grinding that Material would be my way to ensure you could hold the +/-.0001 on diameters in production. I would think even then it would still be a crap shoot to a point with the .002 Profile tolerance on the thing. I would really look at a Rough, Semi-Finish then Finish op for milling. A grinding machine to finish the whole thing would be my choice like a Studer or something along those lines. Risk having too much SFM for the material with grinding and getting stress fractures, but would help you make sure you can hold any tight tolerances required on that Material.

[Guest]

It's the follow ons I'd be terrified of...

Making the first 3 isn't the true headache, it would be those thousands of parts. Let's see if I'm warm

Climate Controlled room for the machine and material, coolant is temperature controlled, glass scales, JAPANESE, 5 decimal place readout, that should do

[Newbeeee™]

^^^^ and I'd finish hone the bore....but whether it's right or not as every inspector I've ever worked with will get a different result with the same gauge!

And you don't want Mr Magoo checking it

[gcode]

Making the first 3 isn't the true headache, it would be those thousands of parts. Let's see if I'm warm

Climate Controlled room for the machine and material, coolant is temperature controlled, glass scales, JAPANESE, 5 decimal place readout, that should do

 

I've got a better idea. Slap the junior engineer silly and tell him to go back and tolerance

his creation for the real world.

[GoetzInd]

Slap the junior engineer silly and tell him to go back and tolerance

his creation for the real world

 

The MTB says .0001 repeatably. So what's the problem?

 

Mike