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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
On Mon, 23 Jan 2006 13:37:10 GMT, BottleBob wrote:
Cliff wrote: On Sun, 22 Jan 2006 19:23:49 GMT, BottleBob wrote: Cliff wrote: I never considered it a metal. I know better. Cliff: Who cares what you considered, or didn't consider something? You are confused G. Cliff: It's not my fault that you are unable to support your claim, and seem to be in a snit over it. Ah, but you see ...... I know what metals are G. Opinions aren't facts, And you opine is that Carbides are metals. LOL .... Heh, let's call it a working hypothesis, which can change when convincing contradicting evidence is presented. So after hundreds of years of folks knowing what metals are your lint has a better idea? let's see some facts/evidence. You don't seem to know, eh? Lint attack again? You're the one that said you "knew better", yet you have presented no factual evidence, or even a plausible explanation so far, that in any way contradicts the premise that Tungsten Carbide is a metal. Your lint must be on a roll. The "LMAO" seems to be on you G. Perhaps, perhaps not. LOL No "perhaps" about it, BB. I think Wick got you yet again. I'm not the one that is having trouble backing up his claim. I don't need to GGG. I think we have established beyond a reasonable doubt that Tungsten is a metal. Up early? Too late? Confused? Are you claiming that elemental Tungsten is NOT a metal? Better go look at a periodic table of the elements if you're in doubt. What part of "CARBIDE" was unclear? Do you see the word "CARBIDE" in my sentence above where I said: "I think we have established beyond a reasonable doubt that Tungsten is a metal." But THAT's not at all the subject, now is it? LOL ..... Bottom line, Tungsten carbide is a chemical compound made up of Tungsten metal, carbon, and the metal Cobalt as a binder. But it's NOT a metal G. Well let's just take a look at the properties of metals. WHY? Think you'll find either Carbides or Tungsten Carbide there? I thought I'd find some general properties of metals with which we could compare the properties of Tungsten Carbide, and I did. Have some electrically conductive plastics: http://www.phschool.com/science/scie..._electric.html http://www.boedeker.com/esdmatls.htm http://composite.about.com/library/g...ldef-e1911.htm Ever been nearly blinded by the sun's glare reflecting from glass? LOL .... ================================================= ============= Metals, group of chemical elements that exhibit all or most of the following physical qualities: they are solid at ordinary temperatures; opaque, except in extremely thin films; good electrical and thermal conductors (see Conductor, Electrical); lustrous when polished; and have a crystalline structure when in the solid state. Metallic elements can combine with one another and with certain other elements, either as compounds, as solutions, or as intimate mixtures. A substance composed of two or more metals, or a substance composed of a metal and certain nonmetals such as carbon are called alloys. Good for you. You can copy & paste stuff. So can jb. IMO, copying from credible sources trumps unsupported conjecture and WAG's any day. Knowing the facts is much better than search, copy & paste followed by your lint going more crazy than usual. "Metals," Microsoft® Encarta® Encyclopedia 2000. © 1993-1999 Microsoft Corporation. All rights reserved. ================================================= ============= Tungsten carbide tooling (inserts, end mills, etc.), have the following properties listed above for metals: solid at ordinary temperatures opaque good electrical and thermal conductors (see excerpt below) lustrous when polished and have a crystalline structure when in the solid state sheesh NOW it's "Tungsten carbide tooling" ..... Of course it's Tungsten carbide tooling, what do you think the discussion was about, Carbide Bucky Balls? Are they metals too per your lint? Rocks are opaque too so I suppose that you think that they are metals too ... Do all rocks have good electrical and thermal conductivity? NO! Do all rocks have a crystalline structure? NO! Umm ... you may want to rethink that G. Do all rocks have a luster when polished? NO! Umm ... you may want to rethink that G. ================================================= ============= http://www.hydrocarbide.com/pg6.htm Properties of Tungsten Carbide Thermal Conductivity - Tungsten carbide is in the range of twice that of tool steel and carbon steel. steel =~ Thermal Conductivity 51.9 W/m-K 360 BTU-in/hr-ft²-°F Electrical Conductivity - Tungsten carbide is in the same range as tool steel and carbon steel. Tungsten Carbide, WC =~ Thermal Conductivity 100 W/m-K 694 BTU-in/hr-ft²-°F Natural Diamond =~ Thermal Conductivity 2000 W/m-K 13900 BTU-in/hr-ft²-°F And YOU were just chastising ME for copying and pasting? They have a word for someone that criticizes others for the same things THEY do. LOL Compare & contrast with YOUR wild claims. So Diamond is a metal too? Is Diamond a good conductor of electricity? (Probably the most important aspect of metals and their resultant metallic bonds) NO! ================================================= ============= If carbide end mills weren't electrically conductive they wouldn't make my LED conductive tool length offsetting tool work, but they do. g Tungsten carbide cutting tools sure seem to fit the criteria for metals given above. Nope. Better go look at the property of metals list again and compare it to the properties of Tungsten Carbide. You bias seems to be interfering with your objectivity. Nope. But your lint is having a party. If you have some evidence to the contrary (that's EVIDENCE now - not opinion), let's hear it. http://www.1115.org/archives/kilroy.jpg So the bottom line so far is that you HAVE NOT presented any factual evidence that Tungsten carbide is NOT a metal. I don't have to VBG. Keep guessing !! But yet Tungsten carbide seems to correlate very well with the properties of metals listed from Encarta Encyclopedia. Cobalt does. I posted data on Tungsten Carbide as you may well recall ... Like I said before, let's see some factual EVIDENCE, not unsupported rhetoric, opinions, speculations, WAG's, or misinformation. LOL .... -- Cliff |
#2
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
"Cliff" wrote in message ... I never considered it a metal. I know better. Cliff: Perhaps an olive branch, here. Tungsten carbide, the compound, is not a metal, although it manifests many of the properties of metals. Technically speaking, it's a ceramic, averaging out about 1:1, atom-to-atom, Wolfram to Carbon. However, tungsten carbide _tooling_ is an alloy or solution of the compound and metal (usually cobalt). Just as carbon is not a true metal (yet manifests a number of metal-like properties), I think we can all accept a solution of carbon and iron as being one of the more familiar metals. It may be that pure WxCx is used in tooling, but I cannot remember seeing that. I believe it's too brittle in that form to be useful. LLoyd |
#3
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
Lloyd E. Sponenburgh wrote:
"Cliff" wrote in message ... I never considered it a metal. I know better. Cliff: Perhaps an olive branch, here. Tungsten carbide, the compound, is not a metal, although it manifests many of the properties of metals. Technically speaking, it's a ceramic, averaging out about 1:1, atom-to-atom, Wolfram to Carbon. However, tungsten carbide _tooling_ is an alloy or solution of the compound and metal (usually cobalt). Just as carbon is not a true metal (yet manifests a number of metal-like properties), I think we can all accept a solution of carbon and iron as being one of the more familiar metals. It may be that pure WxCx is used in tooling, but I cannot remember seeing that. I believe it's too brittle in that form to be useful. It's in use as a coating on milling and turning tools. -- John R. Carroll Machining Solution Software, Inc. Los Angeles San Francisco www.machiningsolution.com |
#4
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
On Mon, 23 Jan 2006 16:08:01 GMT, "Lloyd E. Sponenburgh"
wrote: "Cliff" wrote in message .. . I never considered it a metal. I know better. Cliff: Perhaps an olive branch, here. Tungsten carbide, the compound, is not a metal, although it manifests many of the properties of metals. Technically speaking, it's a ceramic, averaging out about 1:1, atom-to-atom, Wolfram to Carbon. So I keep telling him & his lint G. However, tungsten carbide _tooling_ is an alloy or solution of the compound and metal (usually cobalt). Usually the Cobalt is a binder for the sintering IIRC. Just as carbon is not a true metal (yet manifests a number of metal-like properties), I think we can all accept a solution of carbon and iron as being one of the more familiar metals. Actually, there are a lot of phases of things in there. Some are indeed metals, like the Iron. It may be that pure WxCx is used in tooling, but I cannot remember seeing that. I believe it's too brittle in that form to be useful. It's not a metal G. LLoyd Thanks. You should see some of the stuff BB's lint gets up to ... LOL ... Nuns & Aristotle did him in long ago I think. (All in fun & things are learned. Often the hard way ..) -- Cliff |
#5
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
"Cliff" wrote in message ... However, tungsten carbide _tooling_ is an alloy or solution of the compound and metal (usually cobalt). Usually the Cobalt is a binder for the sintering IIRC. I'm reasonably sure that it can serve either as a sintering binder OR be used in a true alloy. I'd have to cite source to back up my claim, but we all know how much ire "cutting and pasting" raises around here. LLoyd |
#6
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
Tungsten carbide by itself is often referred to as a ceramic. Common tungsten carbide tooling is WC grains cemented together with another metal, most commonly cobalt, and referred to sometimes as a cermet, for metal bonded ceramic. However, due to a translation mistake between Japanese and English, commonly, means a Titanium based material such as TiC, TiN, or TiCN. They do use "Binderless" carbide for nozzles, etc. where impact is not an issue. The term "Binderless" is open for discussion. As two of the participants have pointed out the language is a bit unclear here. The great majority of the leaders in these fields seem to be willing to accept a variety of terms somewhat interchangeably. The generally accepted manner of discourse in this filed, when one hears a term that is not immediately clear, is to politely question the speaker. This morning I used the term "cermet" and the listener asked if I meant a material with a nickel alloy binder. Actually I did but my focus was on the titanium component and I explained that to him. Because he was sophisticated technically and socially we had a lovely conversation and found we were using many similar terms with different meanings. tom |
#7
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
On Mon, 23 Jan 2006 16:08:01 GMT, "Lloyd E. Sponenburgh"
wrote: ,; ,;"Cliff" wrote in message ... ,; I never considered it a metal. I know better. ,; ,; Cliff: ,; ,;Perhaps an olive branch, here. Tungsten carbide, the compound, is not a ,;metal, although it manifests many of the properties of metals. Technically ,;speaking, it's a ceramic, averaging out about 1:1, atom-to-atom, Wolfram to ,;Carbon. ,; ,;However, tungsten carbide _tooling_ is an alloy or solution of the compound ,;and metal (usually cobalt). Just as carbon is not a true metal (yet ,;manifests a number of metal-like properties), I think we can all accept a ,;solution of carbon and iron as being one of the more familiar metals. This is not correct. Tungsten carbide is a compound but the finished product you refer to as "tungsten carbide _tooling" is better called cemented tungsten carbide. The cobalt is not in solution but is found at the interface as a glue (cement). In practice the cemented carbide tools frequently are a mixture of carbides cemented with cobalt metal. ,; ,;It may be that pure WxCx is used in tooling, but I cannot remember seeing ,;that. I believe it's too brittle in that form to be useful. ,; ,; ,;LLoyd ,; |
#8
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
On Mon, 23 Jan 2006 17:29:27 GMT, "Lloyd E. Sponenburgh"
wrote: ,; ,;"Cliff" wrote in message ... ,;However, tungsten carbide _tooling_ is an alloy or solution of the ,;compound ,;and metal (usually cobalt). ,; ,; Usually the Cobalt is a binder for the sintering IIRC. ,; ,;I'm reasonably sure that it can serve either as a sintering binder OR be ,;used in a true alloy. ,; ,;I'd have to cite source to back up my claim, but we all know how much ire ,;"cutting and pasting" raises around here. I worked for the largest producers of cemented tungsten carbide for over thirty years. Believe me when I tell you that the purpose of the cobalt is to cement the carbide particles together. Cobalt "wets" the carbide and is reasonably high melting. Both are essential. Is there some surface penetration? Probably... but it is not an alloy period. I have been retired for over twenty years but my recollection is that the cobalt content runs about 10%. |
#9
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
Unknown wrote:
Tungsten carbide is a compound but the finished product you refer to as "tungsten carbide _tooling" is better called cemented tungsten carbide. The cobalt is not in solution but is found at the interface as a glue (cement). In practice the cemented carbide tools frequently are a mixture of carbides cemented with cobalt metal. Unknown: Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? -- BottleBob http://home.earthlink.net/~bottlbob |
#11
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
"BottleBob" wrote in message
... Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. -- Ed Huntress |
#12
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
Ed Huntress wrote:
"BottleBob" wrote in message ... Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. Ed: A metal-matrix-composite it may very well be. I've recently seen tungsten carbide tooling called "hardmetal" quite frequently. -- BottleBob http://home.earthlink.net/~bottlbob |
#13
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
"BottleBob" wrote in message
... Ed Huntress wrote: "BottleBob" wrote in message ... Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. Ed: A metal-matrix-composite it may very well be. I've recently seen tungsten carbide tooling called "hardmetal" quite frequently. Hardmetal is something else. It's the nickname for a tungsten alloy used mostly for long, skinny boring bars and such. It is not a cutting-tool material; it's used for various kinds of toolholders. And it's not a carbide, oxide, nitride, or other ceramic. It's metal. Like sintered tungsten carbide (the composite material), its Young's Modulus is 'way up there, much greater than that of steel. So it makes a stiff boring bar. I don't remember its other properties for sure but I think it is more self-damping than tungsten carbide, which is better for preventing vibration in long bars. There have been sintered tungsten carbide boring bars, too. -- Ed Huntress |
#14
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
Ed Huntress wrote:
"BottleBob" wrote in message Ed: A metal-matrix-composite it may very well be. I've recently seen tungsten carbide tooling called "hardmetal" quite frequently. Hardmetal is something else. It's the nickname for a tungsten alloy used mostly for long, skinny boring bars and such. It is not a cutting-tool material; it's used for various kinds of toolholders. And it's not a carbide, oxide, nitride, or other ceramic. It's metal. Like sintered tungsten carbide (the composite material), its Young's Modulus is 'way up there, much greater than that of steel. So it makes a stiff boring bar. I don't remember its other properties for sure but I think it is more self-damping than tungsten carbide, which is better for preventing vibration in long bars. There have been sintered tungsten carbide boring bars, too. Ed: The term hardmetal seems to have a pretty wide use. ================================================== ====== http://www.inframat.com/wcdetail.htm Description of Tungsten Carbide Technology – Superfine Tungsten Carbide for Bulk Hardmetal Applications 1. Introduction Tungsten carbide/cobalt (“WC/Co”) is widely used for cutting tools, metal forming tools, mining tools, and wear resistance surfaces, with wide range of applications, ranging from aerospace, automobile, to home appliances. ================================================== ======= ================================================== ======= http://seedcczz.en.ec21.com/GC007221...e_inserts.html Zhuzhou O.E.D Hardmetal Products tungsten carbide indexable inserts ================================================== ======= ================================================== ======= http://www.reade.com/Products/Carbid...n_carbide.html Tungsten Carbide (WC) Powder Typically used for many hardmetal applications such as electronics, metal and plastic machining, wood cutting and other tools. Also used for waste disposal. ================================================== ======= -- BottleBob http://home.earthlink.net/~bottlbob |
#15
Posted to rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
In article , Ed Huntress says...
Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. Cobalt is the binder, and makes up a good deal of the material. The correct term is "Cemented Carbide" for these tools, which is a pretty good name. Basically very hard particles in a binder that is amenable to sintering. Really hard particles embedded in soft, gooey stuff. The hard stuff cuts, the gooey stuff holds it together. Sintering is one of those 'magic' processes whereby materials densifiy under the application of heat. Basically the deal is that one can pick a system where the free energy goes down as the free surface area goes down. There's a net free energy loss as grains grow closer together. I used to work for GTE and they did a lot of that sort of thing, they developed new materials for, I think, Valenite. They had one guy who's job it was to test new concoctions of cutting tools, he had a *huge* lathe, and had stacks of steel bar stock, about 10 inch diameter, by six feet long, for testing the tools. The bar stock had lengthwise slots in it, about a half inch wide, along the entire length. I think they were interested in shock loading the tools with interrupted cuts. g They put the lathe out in a separate building because of the noise. Anyway I bowled with the guy, in the mixed league there. Cemented carbides don't stand up to really abrasive materials like glass-epoxy, or carbon fiber, composites. What happens is the whiskers of very hard carbon or glass tend to 'pick out' the relatively soft cobalt binder, so the individual carbide grains lose their support in the matrix, and eventually drop out. The same thing happens in polycrystaline diamond to some degree, as they also use cobalt metal as a binder. I'm honestly not sure why PCD works so much better than cemented carbide, it may have to do with a relatively higher ratio of diamond to cobalt compared with cemented carbides. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
#16
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
"BottleBob" wrote in message
... Ed Huntress wrote: "BottleBob" wrote in message Ed: A metal-matrix-composite it may very well be. I've recently seen tungsten carbide tooling called "hardmetal" quite frequently. Hardmetal is something else. It's the nickname for a tungsten alloy used mostly for long, skinny boring bars and such. It is not a cutting-tool material; it's used for various kinds of toolholders. And it's not a carbide, oxide, nitride, or other ceramic. It's metal. Like sintered tungsten carbide (the composite material), its Young's Modulus is 'way up there, much greater than that of steel. So it makes a stiff boring bar. I don't remember its other properties for sure but I think it is more self-damping than tungsten carbide, which is better for preventing vibration in long bars. There have been sintered tungsten carbide boring bars, too. Ed: The term hardmetal seems to have a pretty wide use. snip I think these guys have been taking lessons from used billet-aluminum salesmen. g Bob, I covered tooling as an editor and copywriter for 30 years, and had advertising/publicity clients that included Adamas Carbide (remember them?), Hertle GmbH (remember them? g), and Iscar. In all that time, the professionals in the field never, to my recollection, used the term "hardmetal" to refer to a carbide product in my presence. Believe what you want, but we all know how terms get corrupted by the sales and marketing types. Hardmetal is tungsten alloy. "Carbide" refers to sintered metal-matrix ceramic composite. If you Google around you probably can find 100 or maybe 1000 misuses of the term by the come-latelies and by foreign-based companies who have only a vague knowledge of our terminologies. So, enjoy yourself. I offered some information based on a lot of years in that particular field. Take it or leave it as you wish. -- Ed Huntress |
#17
Posted to rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
"jim rozen" wrote in message
... In article , Ed Huntress says... Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. Cobalt is the binder, and makes up a good deal of the material. The correct term is "Cemented Carbide" for these tools, which is a pretty good name. Basically very hard particles in a binder that is amenable to sintering. Really hard particles embedded in soft, gooey stuff. The hard stuff cuts, the gooey stuff holds it together. Sintering is one of those 'magic' processes whereby materials densifiy under the application of heat. Basically the deal is that one can pick a system where the free energy goes down as the free surface area goes down. There's a net free energy loss as grains grow closer together. I used to work for GTE and they did a lot of that sort of thing, they developed new materials for, I think, Valenite. They had one guy who's job it was to test new concoctions of cutting tools, he had a *huge* lathe, and had stacks of steel bar stock, about 10 inch diameter, by six feet long, for testing the tools. The bar stock had lengthwise slots in it, about a half inch wide, along the entire length. I think they were interested in shock loading the tools with interrupted cuts. g They put the lathe out in a separate building because of the noise. Anyway I bowled with the guy, in the mixed league there. Cemented carbides don't stand up to really abrasive materials like glass-epoxy, or carbon fiber, composites. What happens is the whiskers of very hard carbon or glass tend to 'pick out' the relatively soft cobalt binder, so the individual carbide grains lose their support in the matrix, and eventually drop out. The same thing happens in polycrystaline diamond to some degree, as they also use cobalt metal as a binder. I'm honestly not sure why PCD works so much better than cemented carbide, it may have to do with a relatively higher ratio of diamond to cobalt compared with cemented carbides. IIRC, polycrystalline diamond is partially "self-sintered": diffusion-bonded to itself. The small amount of cobalt serves a somewhat different function than the cobalt in sintered carbide, which is more like brazing, with the diffusion-bonding occurring only at the carbide/cobalt interface. There is such a thing as self-sintered carbide, but it's not used for metalworking cutting tools. And there is pure synthetic diamond which has no binder, used as a coating and in very thin chips that are brazed onto a carbide blank, like polycrystalline diamond. It is slightly harder and longer-wearing than sintered polycrystalline diamond. -- Ed Huntress |
#18
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
Ed Huntress wrote:
I offered some information based on a lot of years in that particular field. Take it or leave it as you wish. Ed: I indeed thank you for your input. I just happened to see the term used quite frequently in my researches the last few days. -- BottleBob http://home.earthlink.net/~bottlbob |
#19
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
"BottleBob" wrote in message
... Ed Huntress wrote: I offered some information based on a lot of years in that particular field. Take it or leave it as you wish. Ed: I indeed thank you for your input. I just happened to see the term used quite frequently in my researches the last few days. -- BottleBob Oh, damn, Bob, I have to apologize. My brain was thinking "heavy metal" while my fingers were typing "hardmetal." Let me try to straighten this out before I really confuse anybody who cares. The tungsten alloy boring bars (and insert-type drill shanks, etc.) are called "heavy metal," not "hardmetal." Those are the ones with the properties I mentioned: very high stiffness and good damping. Tungsten is...well, a very heavy metal, as well as being much stiffer than steel. "Hardmetal" is an old slang term for various metal-matrix sintered carbides (as Jim Rosin said, they're also called "cemented carbides," which is an accurate description of what they are): tungsten carbide, tantalum carbide, and chromium carbide (used in gage blocks) for the most part. It's an old term that's been around since the first half of the last century, and it does indeed refer to carbides. My mistake. I'm sorry if I got anyone scratching their heads over this. Brain fart. g -- Ed Huntress |
#20
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
On Mon, 23 Jan 2006 17:29:27 GMT, "Lloyd E. Sponenburgh"
wrote: "Cliff" wrote in message .. . However, tungsten carbide _tooling_ is an alloy or solution of the compound and metal (usually cobalt). Usually the Cobalt is a binder for the sintering IIRC. I'm reasonably sure that it can serve either as a sintering binder OR be used in a true alloy. Sure. There are LOTS of alloys that contain Cobalt. Tungsten Carbide is not one of them or it would not be a ceramic. http://www.alldyne.com/Catalog/PowderCatalog.htm http://www.knovel.com/knovel2/Toc.jsp?BookID=773 From Ed Huntress: http://yarchive.net/metal/diamond_cutting_inserts.html [ Cemented carbides are not 100% silicon carbide in composition. They are sintered of carbide powder in a cobalt metal matrix. I'm sorry to be such an argumentative s.o.b. tonight, but the hard crystals in cemented carbides are tungsten carbide, or tungsten and tantalum carbide, not silicon carbide. And the binder is usually a mixture of iron and nickel, with more or less cobalt added for toughness and high temperature tolerance. But you have the general idea exactly right. g ] I'd have to cite source to back up my claim, but we all know how much ire "cutting and pasting" raises around here. Depends if you know what it's about to begin with G. -- Cliff |
#21
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
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#22
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
On Mon, 23 Jan 2006 17:13:33 -0600, Unknown wrote:
On Mon, 23 Jan 2006 17:29:27 GMT, "Lloyd E. Sponenburgh" wrote: ,; ,;"Cliff" wrote in message m... ,;However, tungsten carbide _tooling_ is an alloy or solution of the ,;compound ,;and metal (usually cobalt). ,; ,; Usually the Cobalt is a binder for the sintering IIRC. ,; ,;I'm reasonably sure that it can serve either as a sintering binder OR be ,;used in a true alloy. ,; ,;I'd have to cite source to back up my claim, but we all know how much ire ,;"cutting and pasting" raises around here. I worked for the largest producers of cemented tungsten carbide for over thirty years. Believe me when I tell you that the purpose of the cobalt is to cement the carbide particles together. Cobalt "wets" the carbide and is reasonably high melting. Both are essential. Is there some surface penetration? Probably... but it is not an alloy period. A quick search at matweb.com for 50% min W, 1% min Co, 5% min C --- [ Search Error None of the materials in the database satisfied the selected criteria. ] No such alloys G. I have been retired for over twenty years but my recollection is that the cobalt content runs about 10%. Other binders & alloyed binders are used as well. -- Cliff |
#23
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OK what is the diferance between carbide and powdered metal ?
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#24
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OK what is the diferance between carbide and powdered metal ?
On Tue, 24 Jan 2006 01:10:19 GMT, BottleBob wrote:
Unknown wrote: Tungsten carbide is a compound but the finished product you refer to as "tungsten carbide _tooling" is better called cemented tungsten carbide. The cobalt is not in solution but is found at the interface as a glue (cement). In practice the cemented carbide tools frequently are a mixture of carbides cemented with cobalt metal. Unknown: Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? BB, Isn't a fish? They can be shiny too. Just a wild guess here. -- Cliff |
#25
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OK what is the diferance between carbide and powdered metal ?
On Tue, 24 Jan 2006 02:13:03 GMT, BottleBob wrote:
Ed Huntress wrote: "BottleBob" wrote in message ... Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. Ed: A metal-matrix-composite it may very well be. I've recently seen tungsten carbide tooling called "hardmetal" quite frequently. Buzzwords .... Now, about Titanium Billet bike wheels .... -- Cliff |
#26
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OK what is the diferance between carbide and powdered metal ?
On Mon, 23 Jan 2006 23:08:20 -0500, "Ed Huntress"
wrote: "BottleBob" wrote in message ... Ed Huntress wrote: "BottleBob" wrote in message Ed: A metal-matrix-composite it may very well be. I've recently seen tungsten carbide tooling called "hardmetal" quite frequently. Hardmetal is something else. It's the nickname for a tungsten alloy used mostly for long, skinny boring bars and such. It is not a cutting-tool material; it's used for various kinds of toolholders. And it's not a carbide, oxide, nitride, or other ceramic. It's metal. Like sintered tungsten carbide (the composite material), its Young's Modulus is 'way up there, much greater than that of steel. So it makes a stiff boring bar. I don't remember its other properties for sure but I think it is more self-damping than tungsten carbide, which is better for preventing vibration in long bars. There have been sintered tungsten carbide boring bars, too. Ed: The term hardmetal seems to have a pretty wide use. snip I think these guys have been taking lessons from used billet-aluminum salesmen. g Bob, I covered tooling as an editor and copywriter for 30 years, and had advertising/publicity clients that included Adamas Carbide (remember them?), Hertle GmbH (remember them? g), and Iscar. In all that time, the professionals in the field never, to my recollection, used the term "hardmetal" to refer to a carbide product in my presence. Believe what you want, but we all know how terms get corrupted by the sales and marketing types. Hardmetal is tungsten alloy. "Carbide" refers to sintered metal-matrix ceramic composite. If you Google around you probably can find 100 or maybe 1000 misuses of the term by the come-latelies and by foreign-based companies who have only a vague knowledge of our terminologies. So, enjoy yourself. I offered some information based on a lot of years in that particular field. Take it or leave it as you wish. Words probably have BB confused again. "Hardmetal" & "hard metal" probably sound exactly the same to him VBG. BTW, Matweb.com has no listing for"hardmetal" nor does the US trademark office. And clearly it would not be a patent matter. Google searches found nothing interesting either shrug. -- Cliff |
#27
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OK what is the diferance between carbide and powdered metal ?
"Cliff" wrote in message
... On Mon, 23 Jan 2006 23:08:20 -0500, "Ed Huntress" wrote: "BottleBob" wrote in message ... Ed Huntress wrote: "BottleBob" wrote in message Ed: A metal-matrix-composite it may very well be. I've recently seen tungsten carbide tooling called "hardmetal" quite frequently. Hardmetal is something else. It's the nickname for a tungsten alloy used mostly for long, skinny boring bars and such. It is not a cutting-tool material; it's used for various kinds of toolholders. And it's not a carbide, oxide, nitride, or other ceramic. It's metal. Like sintered tungsten carbide (the composite material), its Young's Modulus is 'way up there, much greater than that of steel. So it makes a stiff boring bar. I don't remember its other properties for sure but I think it is more self-damping than tungsten carbide, which is better for preventing vibration in long bars. There have been sintered tungsten carbide boring bars, too. Ed: The term hardmetal seems to have a pretty wide use. snip I think these guys have been taking lessons from used billet-aluminum salesmen. g Bob, I covered tooling as an editor and copywriter for 30 years, and had advertising/publicity clients that included Adamas Carbide (remember them?), Hertle GmbH (remember them? g), and Iscar. In all that time, the professionals in the field never, to my recollection, used the term "hardmetal" to refer to a carbide product in my presence. Believe what you want, but we all know how terms get corrupted by the sales and marketing types. Hardmetal is tungsten alloy. "Carbide" refers to sintered metal-matrix ceramic composite. If you Google around you probably can find 100 or maybe 1000 misuses of the term by the come-latelies and by foreign-based companies who have only a vague knowledge of our terminologies. So, enjoy yourself. I offered some information based on a lot of years in that particular field. Take it or leave it as you wish. Words probably have BB confused again. "Hardmetal" & "hard metal" probably sound exactly the same to him VBG. BTW, Matweb.com has no listing for"hardmetal" nor does the US trademark office. And clearly it would not be a patent matter. Google searches found nothing interesting either shrug. It's a term I've heard more from European companies than American ones, but it is an old slang term used here. I had it mixed up when I was typing versus thinking. g The hard part isn't the metal it contains. It's a half-hard metal matrix holding together a hard non-metal. That's the funny thing about the term. -- Ed Huntress |
#28
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OK what is the diferance between carbide and powdered metal ?
On Tue, 24 Jan 2006 07:07:40 -0500, "Ed Huntress"
wrote: It's a term I've heard more from European companies than American ones, but it is an old slang term used here. I had it mixed up when I was typing versus thinking. g BB may be banging various things on his head to see if they are hard ..... in his opine, naturally G. -- Cliff |
#29
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OK what is the diferance between carbide and powdered metal ?
On Tue, 24 Jan 2006 01:10:19 GMT, BottleBob
wrote: ,;Unknown wrote: ,; ,; ,; Tungsten carbide is a compound but the finished ,; product you refer to as "tungsten carbide _tooling" is better called ,; cemented tungsten carbide. The cobalt is not in solution but is found ,; at the interface as a glue (cement). ,; ,; In practice the cemented carbide tools frequently are a mixture of ,; carbides cemented with cobalt metal. ,; ,;Unknown: ,; ,; Ahh but the question IS; can tungsten carbide tooling (since it is an ,;intimate "mixture" of tungsten, carbon, and cobalt), be correctly ,;referred to as metallic or a metal since the finished product has ,;metallic properties? First it is not a mixture of tungsten, carbon, and cobalt. It is a mixture of tungsten carbide and cobalt metal. If you tell me it has metallic properties I would agree. If you tell me it is a metal then I would say you are wrong. Let me give you another example of a product we made. This was a mixture of glass, silver metal, and epoxy. The product was silver coated tiny glass spheres "cemented" together with epoxy. The finished material was used as a conductor in those ancient multi-flash units that mounted on film cameras. There were eight flash bulbs per unit. The epoxy cemented the spheres tight enough so the material conducted electricity. There was damned little silver in this material but those silver coated glass spheres traced on the ciruitboard conducted electricity and the trace looked shinny metallic. This material certainly has metallic properties so by your reasoning you would try to convince me that this material was a metal. Unsuccessfully I might add. Well perhaps not and perhaps now you will see that just because it looks like a metal and has some metallic properites it is not necessarilly a metal. It is different than "if it looks like a duck and quacks like a duck it is a duck. I am a chemist and spent an entire career working in a metallurgy department in a large industrial research labatory so my view of these things probably is different than most in this newsgroup. For my usage as a chemist when you add additional elements in any significant amount it no longer is a metal. Just because the sales and marketing people use terms such as "hardmetal" or "heavymetal" it doesn't fit my definition of a metal. Now if it fits yours I don't have a problem with that but I will tell you that you are going to be on a slippery slope fitting your definition to a lot of commercial products. |
#30
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OK what is the diferance between carbide and powdered metal ?
Cliff wrote:
On Mon, 23 Jan 2006 13:37:10 GMT, BottleBob wrote: It's not my fault that you are unable to support your claim, and seem to be in a snit over it. Ah, but you see ...... I know what metals are G. Cliff: By all means, let's hear your definition of what metals are, and/or their properties. I'm not the one that is having trouble backing up his claim. I don't need to GGG. You don't NEED to? You were bragging about knowing what metals are, but when I challenged you to present some evidence of why you believe Tungsten carbide is NOT a metal all you've got to say is "I don't need to GGG"? Either you know, or you don't. Are you claiming that elemental Tungsten is NOT a metal? Better go look at a periodic table of the elements if you're in doubt. What part of "CARBIDE" was unclear? Do you see the word "CARBIDE" in my sentence above where I said: "I think we have established beyond a reasonable doubt that Tungsten is a metal." But THAT's not at all the subject, now is it? You were responding to what I wrote. I never mentioned carbide in that sentence. I suggest you try reading for content, for a change. g Metallic elements can combine with one another and with certain other elements, either as compounds, as solutions, or as intimate mixtures. A substance composed of two or more metals, or a substance composed of a metal and certain nonmetals such as carbon are called alloys. IMO, copying from credible sources trumps unsupported conjecture and WAG's any day. Knowing the facts is much better than search, copy & paste followed by your lint going more crazy than usual. You claimed to know the facts, but when I asked you to support your position you failed to present any. What do you think that says about your "claimed" knowledge of the facts? Rocks are opaque too so I suppose that you think that they are metals too ... Do all rocks have good electrical and thermal conductivity? NO! Do all rocks have a crystalline structure? NO! Umm ... you may want to rethink that G. Oh? Why? You've never heard of amphorus (non-crystaline), rock? Do all rocks have a luster when polished? NO! Umm ... you may want to rethink that G. Oh? Why? Are you mistaking smoothness for luster? -- BottleBob http://home.earthlink.net/~bottlbob |
#31
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OK what is the diferance between carbide and powdered metal ?
In article , Ed Huntress says...
There is such a thing as self-sintered carbide, but it's not used for metalworking cutting tools. And there is pure synthetic diamond which has no binder, used as a coating and in very thin chips that are brazed onto a carbide blank, like polycrystalline diamond. It is slightly harder and longer-wearing than sintered polycrystalline diamond. I've had occasion to use that PVD (physical vapor depostion) diamond tooling, also made by valenite, as were the PCD inserts I've used. The coated inserts didn't perform as well for my application, which was turning and milling glass/quartz composite. I suspect this was so because they came with a substantial 'hone' on the edge, like most coated tools do - because of the adhesion issues inherent with dead sharp edges. The PCD tooling however came dead sharp, and remained so. I bought several of those, and have only used three of them. And that's because it took three to populate the Ceratip insert-type end mill. Interesting comment about the PCD being 'self-sintering' though. I suspect there's some more of that thermodynamic magic happening there. Believe it or not, there's guys here where I work, that's all they do - eat, live, sleep, and work on phase diagrams for screwy materials. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
#32
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
Unknown wrote:
On Tue, 24 Jan 2006 01:10:19 GMT, BottleBob wrote: ,;Unknown: ,; ,; Ahh but the question IS; can tungsten carbide tooling (since it is an ,;intimate "mixture" of tungsten, carbon, and cobalt), be correctly ,;referred to as metallic or a metal since the finished product has ,;metallic properties? First it is not a mixture of tungsten, carbon, and cobalt. It is a mixture of tungsten carbide and cobalt metal. If you tell me it has metallic properties I would agree. If you tell me it is a metal then I would say you are wrong. Let me give you another example of a product we made. This was a mixture of glass, silver metal, and epoxy. The product was silver coated tiny glass spheres "cemented" together with epoxy. The finished material was used as a conductor in those ancient multi-flash units that mounted on film cameras. There were eight flash bulbs per unit. The epoxy cemented the spheres tight enough so the material conducted electricity. There was damned little silver in this material but those silver coated glass spheres traced on the ciruitboard conducted electricity and the trace looked shinny metallic. This material certainly has metallic properties so by your reasoning you would try to convince me that this material was a metal. Unsuccessfully I might add. Well perhaps not and perhaps now you will see that just because it looks like a metal and has some metallic properites it is not necessarilly a metal. It is different than "if it looks like a duck and quacks like a duck it is a duck. I am a chemist and spent an entire career working in a metallurgy department in a large industrial research labatory so my view of these things probably is different than most in this newsgroup. For my usage as a chemist when you add additional elements in any significant amount it no longer is a metal. Just because the sales and marketing people use terms such as "hardmetal" or "heavymetal" it doesn't fit my definition of a metal. Now if it fits yours I don't have a problem with that but I will tell you that you are going to be on a slippery slope fitting your definition to a lot of commercial products. Unknown: That sounds like an intelligent and reasonable answer. How many metallic properties does a substance have to have before it's considered a metal? -- BottleBob http://home.earthlink.net/~bottlbob |
#33
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OK what is the diferance between carbide and powdered metal ?
On Tue, 24 Jan 2006 13:25:21 GMT, BottleBob wrote:
Unknown: That sounds like an intelligent and reasonable answer. How many metallic properties does a substance have to have before it's considered a metal? LOL ..... What color do you want to paint it now? Lint? -- Cliff |
#34
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OK what is the diferance between carbide and powdered metal ?
On Tue, 24 Jan 2006 13:18:30 GMT, BottleBob wrote:
Cliff wrote: On Mon, 23 Jan 2006 13:37:10 GMT, BottleBob wrote: It's not my fault that you are unable to support your claim, and seem to be in a snit over it. Ah, but you see ...... I know what metals are G. Cliff: By all means, let's hear your definition of what metals are, and/or their properties. Metals are metals, BB. It's sort of like = = = . I'm not the one that is having trouble backing up his claim. I don't need to GGG. You don't NEED to? You were bragging about knowing what metals are, but when I challenged you to present some evidence of why you believe Tungsten carbide is NOT a metal all you've got to say is "I don't need to GGG"? Either you know, or you don't. You & your lint think it's faith-based again? Subject to you two changing your opine again later I suppose .... Why should your opines today be right and the rest of the world's wrong? IMHO The nuns need a paycut. Are you claiming that elemental Tungsten is NOT a metal? Better go look at a periodic table of the elements if you're in doubt. What part of "CARBIDE" was unclear? Do you see the word "CARBIDE" in my sentence above where I said: "I think we have established beyond a reasonable doubt that Tungsten is a metal." But THAT's not at all the subject, now is it? You were responding to what I wrote. I never mentioned carbide in that sentence. I suggest you try reading for content, for a change. g You used it to opine about Carbides .... LOL .... Metallic elements can combine with one another and with certain other elements, either as compounds, as solutions, or as intimate mixtures. A substance composed of two or more metals, or a substance composed of a metal and certain nonmetals such as carbon are called alloys. IMO, copying from credible sources trumps unsupported conjecture and WAG's any day. Knowing the facts is much better than search, copy & paste followed by your lint going more crazy than usual. You claimed to know the facts, but when I asked you to support your position you failed to present any. What do you think that says about your "claimed" knowledge of the facts? That they make mighty fine bait at times GG. OTOH You do catch a lot of lint .... sort of like old boots, right? Rocks are opaque too so I suppose that you think that they are metals too ... Do all rocks have good electrical and thermal conductivity? NO! Do all rocks have a crystalline structure? NO! Umm ... you may want to rethink that G. Oh? Why? You've never heard of amphorus (non-crystaline), rock? You are thinking of glass? Do all rocks have a luster when polished? NO! Umm ... you may want to rethink that G. Oh? Why? Are you mistaking smoothness for luster? Your angle's probably all wrong G. -- Cliff |
#35
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OK what is the diferance between carbide and powdered metal ?
Holy Moly,
After 20+ years in the buainess I am getting things here I never knew before. Thank you Jim Rozen, Unknown and Ed Huntress. Thank you, very much. The "bible" for the carbide industry is the World Directory And Handbook Of Hardmetals And Hard Materials. By Kenneth JA Brookes it makes a great deal of this clear. It is good technically. I think it's main popularity is in its list of grades and suppliers. You take tungsten carbide powder, carbon powder and cobalt powder then mix and sinter them to make tungsten carbide grains bound by cobalt. There can be lots of things in there as carbides and as binders. The ceramic people tend to think of tungsten carbide as metallic because it bends. (Boeing twists 6" strips into spirals.) Tungten carbide people then to think of it as tungsten carbide. Those of us concerned with its chemical properties tend to think of it as both or either depending on what we are doing. Another example is that we have people call and order 50% silver 'solder'. Because of its temeratrue range it is actuallya 'brazing' material. When we need information on it we look it up in the AWS book of 'filler metals'. Tom |
#36
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OK what is the diferance between carbide and powdered metal ?
"Ed Huntress" wrote:
"BottleBob" wrote in message ... Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. And so essentially is steel, which fairly uniformly is considered a metal. jk |
#37
Posted to alt.machines.cnc,rec.crafts.metalworking
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OK what is the diferance between carbide and powdered metal ?
"jk" wrote in message
... "Ed Huntress" wrote: "BottleBob" wrote in message ... Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. And so essentially is steel, which fairly uniformly is considered a metal. The carbon in steel comes in three forms, IIRC, but the one that makes it steel is not a simple mixture or a compound. It is an incorporation into the molecular structure of iron -- the crystal structure -- that stresses the iron crystals. Most hardening mechanisms involve such stress. Some carbon combines with the iron to form iron carbide. Except for cementite structures (a phase of steel), this has little to do with steel's properties. And there can be free carbon in very high-carbon steel, somewhat like the free carbon in cast iron. But composite structures, by convention, are ones in which the matrix and the bound material produce a composite material that shares or combines properties of the two (or more) materials in a significant way. Free carbon in steel does not. Neither does the carbide. Extremely high-alloy HSS, such as CPM Rex 121, actually get some wear resistance from the precipitated carbides. However, the main one there is chromium carbide, not iron carbide. Metals, metalloids, and "metallics" are defined loosely by their properties. For example, silicon metal is just considered a metal by metallurgists. But it has only some of the properties that we associate with metals. Add some carbon, and it's silicon carbide. Add oxygen, and it's sand. -- Ed Huntress |
#38
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OK what is the diferance between carbide and powdered metal ?
In article , Ed Huntress says...
The carbon in steel comes in three forms, IIRC, but the one that makes it steel is not a simple mixture or a compound. It is an incorporation into the molecular structure of iron -- the crystal structure -- that stresses the iron crystals. Most hardening mechanisms involve such stress. Some carbon combines with the iron to form iron carbide. Except for cementite structures (a phase of steel), this has little to do with steel's properties. And there can be free carbon in very high-carbon steel, somewhat like the free carbon in cast iron. But composite structures, by convention, are ones in which the matrix and the bound material produce a composite material that shares or combines properties of the two (or more) materials in a significant way. Free carbon in steel does not. Neither does the carbide. Composites have much coarser mixes of materials. Solid solutions of iron and carbon exist on a much finer, nearly atomic level than say, carbon fiber composite. The motorycle bodywork is composite, the steel in the engine is really a solid solution. To really understand solid state chemistry like that you need to be able to read and figure out what phase diagrams say. These are basically graphs that give the crystalographic details, and the alloying percentages and what temperatures they occur at, for any given combination of materials. Very intricate stuff and a subject I know just barely enough about to make myself dangerous to myself. g Metals, metalloids, and "metallics" are defined loosely by their properties. For example, silicon metal is just considered a metal by metallurgists. But it has only some of the properties that we associate with metals. Add some carbon, and it's silicon carbide. Add oxygen, and it's sand. THe last two are chemical *compounds* of sililcon. Different than a solid solution, or a composite. What properties of silicon do metalurgists call metalic? Its ductility? g Solid state chemistry is a very, very arcane art. At a former employer, they had three of those folks on staff, they wore long flowing robes and pointy hats with planets and stars on them. They were frequently found stirring strange bubbling concoctions in almebics (don't worry, we're just "precalcining" this potion, er I mean, sample) and would lapse into the most amazing jargon whenever I would ask what was going on in some furnace. Oddly enough one of them always heated his tea water on the lab hotplate, and cooked his lunch in one of the furnaces. I'm not sure how he got away with this from an OSHA perspective, or for that matter, on a purely toxicological basis. But he was pretty elderly even then, and no doubt still cooking those samples. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
#39
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OK what is the diferance between carbide and powdered metal ?
On Tue, 24 Jan 2006 10:34:15 -0800, jk wrote:
"Ed Huntress" wrote: "BottleBob" wrote in message ... Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. And so essentially is steel, which fairly uniformly is considered a metal. Now that everyone is awake .... a bit back someone was touting an alloy of less than 50% Iron with no Carbon (IIRC) as a steel ..... X-750 nickel superalloy? SermaLoy 1515? They were also claiming that jet engine turbne blades were made of Chromium Steel .... G. -- Cliff |
#40
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OK what is the diferance between carbide and powdered metal ?
On Tue, 24 Jan 2006 18:57:10 -0500, "Ed Huntress"
wrote: "jk" wrote in message .. . "Ed Huntress" wrote: "BottleBob" wrote in message ... Ahh but the question IS; can tungsten carbide tooling (since it is an intimate "mixture" of tungsten, carbon, and cobalt), be correctly referred to as metallic or a metal since the finished product has metallic properties? Neither one, Bob. It's a metal-matrix composite. Think about reinforced epoxy. 'Same thing. And so essentially is steel, which fairly uniformly is considered a metal. The carbon in steel comes in three forms, IIRC, but the one that makes it steel is not a simple mixture or a compound. It is an incorporation into the molecular structure of iron -- the crystal structure -- that stresses the iron crystals. Most hardening mechanisms involve such stress. Some carbon combines with the iron to form iron carbide. Except for cementite structures (a phase of steel), this has little to do with steel's properties. And there can be free carbon in very high-carbon steel, somewhat like the free carbon in cast iron. But composite structures, by convention, are ones in which the matrix and the bound material produce a composite material that shares or combines properties of the two (or more) materials in a significant way. Free carbon in steel does not. Neither does the carbide. Extremely high-alloy HSS, such as CPM Rex 121, actually get some wear resistance from the precipitated carbides. However, the main one there is chromium carbide, not iron carbide. Consider Cast Irons .... Metals, http://www.lenntech.com/periodic-chart.htm metalloids, and "metallics" are defined loosely by their properties. http://www.shodor.org/unchem/basic/atom/ http://www.sciencebyjones.com/shells.htm For example, silicon metal is just considered a metal by metallurgists. A semiconductor ... But it has only some of the properties that we associate with metals. Add some carbon, and it's silicon carbide. Add oxygen, and it's sand. -- Cliff |
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