The stainless from hell
Bruce Simpson wrote: I've done a lot of machining on stainless in recent years and found that once I became accustomed to things such as work-hardening, using low speeds and agressive cuts, it's not so bad. However, yesterday I encountered the piece of stainless from hell. It laughed at my M42 toolbits, rounding off the edges within moments of contact -- no matter that I'd ground back the surface to remove possible work-hardening, that I used good quality cutting lube, that I had sharpened and honed the tool perfectly adn that my SFM and depth of cut were what I normally use for SS. Even carbide tooling doesn't cope well with this stuff (I've gone through three inserts already when normally they last ages on SS). I guess this is the price you pay for picking up bits of scrap from time to time rather than buying a known alloy off the shelf. I don't know what alloy this is but it's non-magnetic (austenitic?) and, based on its awful hardness, certainly doesn't seem to be 303, 304 or 316. Maybe it's not SS at all but that most elusive of all alloys -- impervium! I think you are getting warm! It sounds like hard Chromed shafting. It is nearly impossible to machine, but can be ground nicely. It may look like SS, but one giveaway to some pieces is the mirror ground finish. Jonm |
The stainless from hell
I've done a lot of machining on stainless in recent years and found
that once I became accustomed to things such as work-hardening, using low speeds and agressive cuts, it's not so bad. However, yesterday I encountered the piece of stainless from hell. It laughed at my M42 toolbits, rounding off the edges within moments of contact -- no matter that I'd ground back the surface to remove possible work-hardening, that I used good quality cutting lube, that I had sharpened and honed the tool perfectly adn that my SFM and depth of cut were what I normally use for SS. Even carbide tooling doesn't cope well with this stuff (I've gone through three inserts already when normally they last ages on SS). I guess this is the price you pay for picking up bits of scrap from time to time rather than buying a known alloy off the shelf. I don't know what alloy this is but it's non-magnetic (austenitic?) and, based on its awful hardness, certainly doesn't seem to be 303, 304 or 316. Maybe it's not SS at all but that most elusive of all alloys -- impervium! -- you can contact me via http://aardvark.co.nz/contact/ |
The stainless from hell
On Tue, 14 Oct 2003 16:41:41 -0500, Jon Elson
wrote: Bruce Simpson wrote: I've done a lot of machining on stainless in recent years and found that once I became accustomed to things such as work-hardening, using low speeds and agressive cuts, it's not so bad. However, yesterday I encountered the piece of stainless from hell. It laughed at my M42 toolbits, rounding off the edges within moments of contact -- no matter that I'd ground back the surface to remove possible work-hardening, that I used good quality cutting lube, that I had sharpened and honed the tool perfectly adn that my SFM and depth of cut were what I normally use for SS. Even carbide tooling doesn't cope well with this stuff (I've gone through three inserts already when normally they last ages on SS). I guess this is the price you pay for picking up bits of scrap from time to time rather than buying a known alloy off the shelf. I don't know what alloy this is but it's non-magnetic (austenitic?) and, based on its awful hardness, certainly doesn't seem to be 303, 304 or 316. Maybe it's not SS at all but that most elusive of all alloys -- impervium! I think you are getting warm! It sounds like hard Chromed shafting. It is nearly impossible to machine, but can be ground nicely. It may look like SS, but one giveaway to some pieces is the mirror ground finish. Jonm It could be a chunk of Inconel. Gunner "You cannot invade the mainland United States. There would be a rifle behind each blade of grass." --Japanese Admiral Isoroku Yamamoto |
The stainless from hell
Or something like A-286. Rather nasty being 25% nickel IIRC. It can be
rather indifferent to tooling if one attempts to run it just a bit too fast. Almost certainly, whatever it might be, sounds like something I put in the category of "gawdawfulsqueaky****". michael |
The stainless from hell
Maybe hastaloy....shudder.
Les |
The stainless from hell
On Tue, 14 Oct 2003 16:41:41 -0500, Jon Elson
wrote: Bruce Simpson wrote: I've done a lot of machining on stainless in recent years and found that once I became accustomed to things such as work-hardening, using low speeds and agressive cuts, it's not so bad. However, yesterday I encountered the piece of stainless from hell. It laughed at my M42 toolbits, rounding off the edges within moments of contact -- no matter that I'd ground back the surface to remove possible work-hardening, that I used good quality cutting lube, that I had sharpened and honed the tool perfectly adn that my SFM and depth of cut were what I normally use for SS. Even carbide tooling doesn't cope well with this stuff (I've gone through three inserts already when normally they last ages on SS). I guess this is the price you pay for picking up bits of scrap from time to time rather than buying a known alloy off the shelf. I don't know what alloy this is but it's non-magnetic (austenitic?) and, based on its awful hardness, certainly doesn't seem to be 303, 304 or 316. Maybe it's not SS at all but that most elusive of all alloys -- impervium! I think you are getting warm! It sounds like hard Chromed shafting. It is nearly impossible to machine, but can be ground nicely. It may look like SS, but one giveaway to some pieces is the mirror ground finish. Jonm Got me. I did get some SS that seems to have rocks in it from a dumpster. The other stuff seems to be fine , but makes me wonder why they tossed 20' lengths of SS. BTW, I stopped by that dumpster today and it was gone along with the lazer stuff in the shop. The doors were wide open and not a machine in sight. There is another building behind that , that the same guy owns , but there was a cop setting right by where the dumpter sat and I didn't want to look around to much. Wonder if the biggest machine shop in town folded . The guy had given me a complete tour of the place and I only saw two vertical mills the rest where CNC and cool bolt makers that heat them up with elec. Time to find the guy , but I'm busy. Anyhow, lost my best dumpster diving place even though some of the stuff should be in the dumpster. |
The stainless from hell
On Tue, 14 Oct 2003 16:41:41 -0500, Jon Elson
wrote: I think you are getting warm! It sounds like hard Chromed shafting. It is nearly impossible to machine, but can be ground nicely. It may look like SS, but one giveaway to some pieces is the mirror ground finish. It's not hard-chromed, I cut it to length and even a facing cut just knocks the tooling about something awful. I don't think it's one of the high-nickel alloys either. I've machined a little Inconel before and although it's nastier than 316 stainless, it's nowhere near as bad as this. I'm glad I didn't try to mill any of it -- it would have trashed my cutters in no-time flat. At least on the lathe I was able to regrind the tooling until I figured I was wasting my time. Could it have been drawn or rolled so as to make the whole thing work-hardened right through perhaps? In that case, would annealing it make any difference -- does annealing relieve work-hardening? -- you can contact me via http://aardvark.co.nz/contact/ |
The stainless from hell
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The stainless from hell
In article , Bruce Simpson
wrote: On Tue, 14 Oct 2003 16:41:41 -0500, Jon Elson wrote: I think you are getting warm! It sounds like hard Chromed shafting. It is nearly impossible to machine, but can be ground nicely. It may look like SS, but one giveaway to some pieces is the mirror ground finish. It's not hard-chromed, I cut it to length and even a facing cut just knocks the tooling about something awful. I don't think it's one of the high-nickel alloys either. I've machined a little Inconel before and although it's nastier than 316 stainless, it's nowhere near as bad as this. I'm glad I didn't try to mill any of it -- it would have trashed my cutters in no-time flat. At least on the lathe I was able to regrind the tooling until I figured I was wasting my time. Could it have been drawn or rolled so as to make the whole thing work-hardened right through perhaps? In that case, would annealing it make any difference -- does annealing relieve work-hardening? -- you can contact me via http://aardvark.co.nz/contact/ Could it be a cobalt alloy? |
The stainless from hell
On Wed, 15 Oct 2003 05:56:44 GMT, Ernie Leimkuhler
wrote: Could it be a cobalt alloy? Not impossible I guess -- it came from a large industrial plant but I don't know what it was being used for before I got my hands on it. I've given up actually using it for anything (other than destroying perfectly good tooling ;-) , but the challenge of identifying it remains. -- you can contact me via http://aardvark.co.nz/contact/ |
The stainless from hell
"Bruce Simpson" wrote in message ... On Wed, 15 Oct 2003 05:56:44 GMT, Ernie Leimkuhler wrote: Could it be a cobalt alloy? Not impossible I guess -- it came from a large industrial plant but I don't know what it was being used for before I got my hands on it. I've given up actually using it for anything (other than destroying perfectly good tooling ;-) , but the challenge of identifying it remains. I had a like experience several years ago when an old friend needed a part made from "stainless". He was employed at the huge open pit copper mine in Utah, from which he brought me a piece of stock he claimed was stainless. My experience in cutting that material parallels yours. I've cut most all of the metals, Hastalloy, A 286, you name it, including titanium, but I've never experienced anything like this stuff. I have no idea what it is or was, but I think I still have the rem somewhere in my storage. I hope to never see it on the machine again! Harold |
The stainless from hell
"Bruce Simpson" wrote in message ... I guess this is the price you pay for picking up bits of scrap from time to time rather than buying a known alloy off the shelf. Next time you might bring a file with you......you could also check to see how easily you can dent it by whacking a corner of it with a fairly sharp edge of another heavier piece of metal (concentrates the impact.) I don't know what alloy this is but it's non-magnetic (austenitic?) and, based on its awful hardness, certainly doesn't seem to be 303, 304 or 316. I usually buy "drops " ( some places call them "rems" ) from the steelyard or from a bigger machine shop when I need small quantities... While you cant usually get material certifications from this source, the guy running the saw typically remembers what material each piece in the drop box was cut from.......and often the color code was left intact. -- SVL |
The stainless from hell
Bruce Simpson wrote in message . ..
Bruce, Since you are in New Zealand maybe it has to be run clockwise :-). Remember, The early bird gets the worm BUT it's the second mouse that gets the cheese George |
The stainless from hell
"Bruce Simpson" wrote in message
... On Wed, 15 Oct 2003 05:56:44 GMT, Ernie Leimkuhler wrote: Could it be a cobalt alloy? Not impossible I guess -- it came from a large industrial plant but I don't know what it was being used for before I got my hands on it. I've given up actually using it for anything (other than destroying perfectly good tooling ;-) , but the challenge of identifying it remains. Heck, maybe you should trying to make it INTO tooling? |
The stainless from hell
--Had to machine some components once out of something similarly
nasty. The stuff had been annealed B4 I got it (supplied by the customer); but was still extremely nasty. Might you have a go at annealing it and try again?? -- "Steamboat Ed" Haas : Screw the governors... Hacking the Trailing Edge! : Recall that $87 billion!! http://www.nmpproducts.com/intro.htm ---Decks a-wash in a sea of words--- |
The stainless from hell
Just looked it up and the machinability rating on Nitronic 60 is 23%
I assume this is relative to carbon steel Any chance it is 17-4 or 17-6 precipitation hardened stainless? Koz Ned Simmons wrote: In article , says... On Tue, 14 Oct 2003 16:41:41 -0500, Jon Elson wrote: I think you are getting warm! It sounds like hard Chromed shafting. It is nearly impossible to machine, but can be ground nicely. It may look like SS, but one giveaway to some pieces is the mirror ground finish. It's not hard-chromed, I cut it to length and even a facing cut just knocks the tooling about something awful. I don't think it's one of the high-nickel alloys either. I've machined a little Inconel before and although it's nastier than 316 stainless, it's nowhere near as bad as this. I'm glad I didn't try to mill any of it -- it would have trashed my cutters in no-time flat. At least on the lathe I was able to regrind the tooling until I figured I was wasting my time. Could it have been drawn or rolled so as to make the whole thing work-hardened right through perhaps? In that case, would annealing it make any difference -- does annealing relieve work-hardening? Armco Nitronic 50 or Nitronic 60 is another possibility. It's non-magnetic, very tough, and nasty to machine. It's often used for pump shafts in corrosive media and for prop shafts. It's been a long time, but I think recommended cutting speeds are about half that of 304/316. Ned Simmons |
The stainless from hell
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The stainless from hell
Not quite the same, but recently I cut some small parts out of some
7-17 ph stainless and tried to silver solder them. After that did not work, I looked in some reference material and found that regular silver solder is not recommended for 7-17 ph. Naturally the local welding supply shops have not heard of more than one kind of silver solder. I remade the parts out of other material. Dan |
The stainless from hell
On Wed, 15 Oct 2003 19:32:46 +1300, Bruce Simpson
wrote: On Wed, 15 Oct 2003 05:56:44 GMT, Ernie Leimkuhler wrote: Could it be a cobalt alloy? Not impossible I guess -- it came from a large industrial plant but I don't know what it was being used for before I got my hands on it. I've given up actually using it for anything (other than destroying perfectly good tooling ;-) , but the challenge of identifying it remains. Should be forgable if you wanted to ahve a go at it. If you are ever coming up to Civilisation again, throw some into the car adn I will give it a try. might be ok for tools or something... Geoff |
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