Hardest Material
Not to long ago I've started at a shop that specializes it harder than normal steel. Mostly ar500 and chromium overlay. Has me curious, what is the hardest material you routinely work with?
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I worked in mainly non-ferrous materials for years… I used to think that 4140 was relatively “hard.” Now… inconel and titanium are possible…
Congrats on the new job…
Thank you. What would you machine inconel with? Is carbide strong enough.
REALLY rigid machines and lots of improved insert technology… 🤓
4140 is butter against inconel or titanium
Titanium didn't seem all that bad the few times I've done it? I was able to machine it pretty easily on a manual lathe, I'd say it was less trouble than stainless even. Possibly different grades?
Inconel x-750 was one of the strangest metals I’ve had to work with. It likes slow and deep cuts, fast and fine, a pain to thread and warping while turning on really small parts was an expensive learning experience.
Absolutely agree with inconel for hardness… but if we’re talking “strangest” (or said another way: one that surprised me most) Magnesium was one that caught my attention/curiosity… It was super easy to cut but had a level of malleability that sometimes changed order of operations and it highlighted the potential speed of galvanic corrosion.
Sorry for the hi-jack… (back to the regularly scheduled material hardness topic) …just got me thinking about “strangest.”
No need to be sorry. Strange is close enough.
We don't do much weird stuff, probably the weirdest is aluminum-bronze. Cuts like butter in a lathe, but try to use the band saw and you'll be cutting the same 9" piece for hours.
Lol going with strangest.... rubber in a mill. Get the setup just right then go throw the part in a freezer for a while..... then run to the machine, throw it in and hit the button and hope it stays cold long enough 🤣🤣
My shop specializes in a chromium carbide weld overlay on some of our components. Shatters almost any tool
Thats my shop's bread and butter. I'm in a small fab shop attached to a weld shop. All day the robots are welding big sheets.
Today I got to machine Amy company only alloy. It's like a thru hardened to about 55 rock, it is extremely abrasion and impact resistant. Idk what's all in it, but it flexes almost like spring steel
Tungsten Carbide weld overlay wear liners. Hard as woodpecker lips and miserable to work with.
Luckily we machine before our tungsten overlay
Just today I hard turned some HRC 62 D2 tool steel.
The right sfm and cbn insert and it's just like cutting crs!!
Zirconia ceramic and tungsten carbide. By routinely, it's a couple of times a week. Nothing but diamond grinders for those two. But man. It's easy to put a mirror finish on em.
Zirconia was the fucking nightmare of my career. Probably the worst I'll ever deal with. I had to design and tune a machine to make false baby teeth, 0.35mm wall thickness shells, a 100mm diameter disc 15mm thick, had about 50 teeth cut into it, took 15 hours. One bad look at the plate and it would explode.
Hardest for toughness of material - stellite
Most difficult to cut because it's strange.
Teflon and Nickel
Why does Teflon have to feel like you are machining pasta, I hate it
Drilling EL50 was a bastard. You got to drill 3 parts in one. First was entering the hard candy shell, next was plowing through the gummy center, before finally shattering the drill on break-out of the hard candy shell. Only 49 more holes and this round way will be ready to ship. 19 sticks to go!
Ended up milling a counterbore to the gummy part, drilling that, and using a longer endmill to break out. That actually worked well.
Define hard though.
Cobalt 3 runs about 55 Rockwell and is best cut with circular ceramic inserts at a high sfm and low feed
Inconel 625 is a "hard" metal to work with but isn't necessarily hard in a brittle sense. Inconel can be cut fairly easily with carbide and the correct sfm/feed/tooling setup
Ceramics inserts on a shouldermill are a total game changer for roughing inconel... Everything is ass backwards... 11,000 RPM, 200 IPM... Sparks flying everywhere, no coolant. You need a carbide endmill for finishing, but it's hella faster.
Yeah, I'll leave that to you guys who watch through a window. As someone standing next to a spinning chuck and running the controls, I'm not playing the dodge the hot flesh searing chips game. That game sucks. 🤣🤣
440c sucks big D especially when the boss man orders it heat treated prior to machine (I know your reading this 😂)
Inconel is always a pain in the dick, but man, I had this waspaloy come through one time and boy did I struggle.
I used to machine castings for railroad turnouts and crossings that are made with manganese. They weren’t super “hard” just a pain in the ass. Massive tools with lots of inserts and no coolant. We would burn through inserts like nobody’s business. As for the strangest, I would have to say oil impregnated bronze. Wasn’t difficult to machine but holy shit, that oil gets everywhere. When they say impregnated, they mean it’s going to impregnate the operator too.
Mp35n
Ugh. To all the people that complain about Inconel, be thankful it's not Mp35n.
Caldie heat treated to 58-60RC. Occasional some of the pre purchased mold components that we use need to be modified and some of those are made of H13 (typically) that’s heat treated to 70-72RC.
We did some parts that were an inconel stainless alloy I think. Otherwise AR400 is the hardest, along with maybe 4340 HT.
Machine Titanium all the time, it's butter compared to the Super Alloys, notably Hastalloy. When you say hard though, I'm taking you to mean difficult to machine.
Sintered Zirconia is the hardest material I've ever machined, can only grind it.
4140 i fucking hate it .
Stellite alloys, inconel, titanium inside aluminum bronze, some stupid stainless for boeing