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Machining Nickel 200

Mud

Diamond
Joined
May 20, 2002
Location
South Central PA
I have some parts to make from Nickel 200/201, and have never dealt with it. How does this machine, and how is it on tools? I need to buy material for 1" X 2.5" blocks, any suggestions where to buy small quantities? Is this supplied in material like cold rolled mild steel, where the finish on the bars is nice enough to use for loose tolerance parts like heat sinks or do I need to buy oversize and machine all 6 sides?
 
Actually, 200/201 doesn't machine too bad. About 90 SFM with HSS. It's doesn't work harden because there's no alloy. It does dull tools in a hurry.

You don't get a lot of selection in material. Common is round bar with max at 2-3". You can get sheet, but either 3/8 or 1/2 is the max. Online Metals or Performance alloys.
JR
 
Eventually I will. I was hoping to get real world advise from someone who had done it, rather than a tool rep. Otherwise I would have just called the reps.



So you've only turned it, no milling?
As I said use a positive rake, with a grade for nickel alloys, the stuff is soft , gummy and abrasive.
We used to turn some shafts out of pure Nickel, have milled flats but Im certainly not an expert.
We just found that Inserts designed for Inconel, Monel, and nickel alloys works about the best, are there inserts made specifically for Nickel, I doubt it!
Nickel likes to be cut not pushed, hence the positive rake.
A good HSS end mill should work fine for small run jobs.
 
Howdy,

I have milled piles of Ni200. It machines well with soluble oil flood coolant. The minimum oil mist I have does not pull heat away fast enough an makes an irritating smoke. Sharp sturdy tools are a must. I don't bother with HSS. Speed can be your friend in the nickel alloys, but the low thermal conductivity of the Ni makes for high cutting edge temps; The limiting factor. The material will abrade cutters, but not terribly. The cutting edge temperature is the real killer. If you have experience milling titanium, nickel alloys are similar. Sturdy fixtures are important. Getting the most metal removed per flute engagement is key to milling economy, and tool usage economy. My advice, get a block of nickel and run your own tests using your programming style, your tooling, and machinery. My recipe works for me, but it is the result of years of failures and testing and is not likely to work in all situations.

Fantastic surface finishes can be achieved in Ni200/200 with good carbide and good practices. My favorite roughing cutters are Kennametal inserted button cutters with high positive insert, I run them using every last drop of spindle HP. Finish with solid carbide. If you can't see your reflection in your nickel parts there is still opportunity for improvement. Micromilling Ni and refractory alloys is the tricky part... all the normal rules break down when your roughing with a 1mm end mill.
 
Thanks lowdown, that's good info. How about drilling, does it drill like titanium? I have some 1/2" dia X 6" deep holes to drill, how would you approach that? Small quantities, not enough to invest in gundrills and etc.
 
IMO, it drills like a piece of rebar.

For a 6" deep hole, we'd run it on something that had a ChipBlaster. Doesn't mater, we've got the CB on both lathes and machining centers. They do make a difference in deep drilling.

Now, having said that, there is probably nothing that would come our way anymore that we couldn't figure out a way to get into one of the lathes (Puma 400L) or one the vertical or horizontal machining centers that had a ChipBlaster. But, somebody could order a 20" pure nickel body in which case we'd use the radial drill and just flood the hole and peck often.

Drills would be Guhring with the Firex coating in a 15D length. Guhring, Inc. - Tool List
probably start out at 350 SFM http://www.guhring.com/documents/tech/speedfeed/6509.pdf
JR
 
Hi Mud,

I second the ChipBlaster! Impressive but pricey! I have also had good luck with the Guhring drills. Often they seem to be the only people who grind such drills. I have had good luck with OSG Helios drills also, but I reach for the Guhring catalog first. I have never found drilling Nickel alloys to be particularly enjoyable. Especially at the D/L ratios you describe. Lots of coolant, through the tool if you have it. Lots of heat is generated at the drill tip as you would expect. Sturdy split point geometry is a must... At least if it's nearly pure nickel it won't work harden like the high temp alloys. In very high Ni alloys The chips form and stick to the flutes like poor quality aluminum. The Guhring Firex coating does a good job of preventing adhesion of the chip. If you have lots of holes, it would be worth investigating whether or not your machine can 'sense' Z axis pressure and if so, can you monitor or have the machine through an alarm if reaches a certain limit. Watching the Z load is about the only method I have found for determining if the drill is loading up (or melting) in the bottom of a deep hole.

Use a stubby drill a few tenths over your long drill to pilot the hole. Variable peck depth on the deep drilling helps... 1st peck 1.0, 2nd peck .75...etc. It might be that the last two inches have to be drilled at .050 peck to keep things cool and clear chips.
 
I have some parts to make from Nickel 200/201, and have never dealt with it. How does this machine, and how is it on tools? I need to buy material for 1" X 2.5" blocks, any suggestions where to buy small quantities? Is this supplied in material like cold rolled mild steel, where the finish on the bars is nice enough to use for loose tolerance parts like heat sinks or do I need to buy oversize and machine all 6 sides?

You can check the website for much useful information on Nimonic 90 Nimonic 90 Round Bars Manufacturers & Supplier - Nextgen Steel & Alloys
 








 
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