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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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Is tungsten carbide ferrous?
Is tungsten carbide ferrous?
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Is tungsten carbide ferrous?
"benwoodward.com" wrote:
Is tungsten carbide ferrous? I would think not. AFAIK, a metal needs to contain iron to be called ferrous. Hence the name ferrous, from the Latin for iron, ferrum. -- Abrasha http://www.abrasha.com |
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Is tungsten carbide ferrous?
In article , David A. Webb says...
Even if some iron powder was added, it probably isn't considered "ferrous". Binders in this case often contain a large amount of cobalt. While cobalt is magnetic (this may be what the original poster was getting after?) it does not qualify the material as being ferrous. Jim ================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ================================================== |
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Is tungsten carbide ferrous?
On 5 Feb 2004 10:38:56 -0800, (benwoodward.com)
wrote: Is tungsten carbide ferrous? No Mark Rand RTFM |
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Is tungsten carbide ferrous?
How can it be magnetic and not be ferrous?
Can it rust? Can it be welded to steel? Welded with steel? Also, if I quench harden 2016, why won't it cut carbide? Can tungsten carbide be quench hardened? Forged? I wonder. |
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Is tungsten carbide ferrous?
"benwoodward.com" wrote in message
om... How can it be magnetic and not be ferrous? It can be ferromagnetic. Like the word phosphorescence, which now has nearly nothing(?) to do with phosphorous (which has only a weak phosphorescent effect anyway). Can it rust? Rust is a specific form of oxide, ferric (III) oxide, so it can only form where there's iron. Can it be welded to steel? Welded with steel? Same thing? I doubt it, due to brittleness and differences in expansion rate. But I wouldn't know. Also, if I quench harden 2016, why won't it cut carbide? Something can only be cut by something harder...obviously, carbide needs to be cut with something a *lot* harder than steel. Like say, diamond. Unless you reversed your statement, in which case, I don't know what the specs are on cutting 2016 (aluminum? steel?) with carbide. Can tungsten carbide be quench hardened? Forged? No. As far as I know it's a brittle material and can only be formed by casting (since it melts upwards of 5200°F, um, ...no), sintering or abrasive means of material removal (grinding, etc.). Being a definite chemical (WC) I doubt it has different phases, so all a quench would do is crack it. It's brittle, remember? Now... I'll let someone like Ed H. correct me  Tim -- "That's for the courts to decide." - Homer Simpson Website @ http://webpages.charter.net/dawill/tmoranwms |
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Is tungsten carbide ferrous?
"benwoodward.com" wrote in message
om... How can it be magnetic and not be ferrous? Many tungsten carbide formulations contain cobalt power, which is magnetic. Some tungsten carbide formulations (not, generally, ones used for cutting tools) contain iron powder. Can it rust? Only if it contains iron powder. Can it be welded to steel? Nope, unless you want to count exotic techniques such as electron-beam welding. You can't weld it at home. It can be brazed to steel very nicely, however. Welded with steel? I don't get the distinction. Also, if I quench harden 2016, why won't it cut carbide? Carbide runs around 10 points higher on the Rockwell C hardness scale than the hardest steel. Can tungsten carbide be quench hardened? No. Forged? Not really. Maybe you need a better explanation of what the material is. Tungsten carbide is a ceramic; a compound of carbon and tungsten, WC. Like most engineering ceramics, it's harder than any steel. It won't melt at the temperatures you can achieve in a shop. When they make a tool out of tungsten carbide, they start with a powder ground from tungsten carbide crystals. Then they add powders of various metals to serve as a binder. When the application involves high temperatures, as with cutting tools, those metal additions are usually high-melting-point metals plus some others that are needed to achieve good bonding. Nickel and cobalt are common ones. Other metals, such as iron, may be used for lower-temp applications, such as wear parts for process machinery that doesn't run hot. The powders are compressed in a die and then sintered. Sintering involves heating the compressed form in an oven until the binders reach a temperature just below their liquid state. They bond to each other, and to the particles of WC, by diffusion bonding, rather than by liquid welding. The result is a kind of pudding, like concrete, with WC particles as the aggregate and diffusion-bonded metal as the cement. The total mass has a hardness somewhat below that of pure WC but well above that of steel. Any heat-treatment done to the part would be based on the heat-treatment characteristics of the metal binders. And, unlike steel, they generally don't heat-harden. Ed Huntress |
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Is tungsten carbide ferrous?
Thank you for your replies. TC is a ceramic then. I was totally
unaware just how alien to steel tc is. I'm classifying it under 'alien technology successfully reverse engineered' and leaving it at that.:-) |
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Is tungsten carbide ferrous?
In article , benwoodward.com
says... Thank you for your replies. TC is a ceramic then. Umm, I would say not a ceramic. There are many different definitions of ceramic but I think the best description of things like WC or TC would be a "cemented carbide." Cemented because it's the binder (typically cobalt) that cements the harder particles together. The notion of sintering is actually pretty complicated - why does the density go up, and the porosity down, when a bunch of powder is heated? Turns out that as the temperature goes up, the free energy for the boundaries is such that the minimum energy state of a powder like that has the maximum contact between grains. I hesitate to point this out, but that's another thermodynamic thing. Jim ================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ================================================== |
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Is tungsten carbide ferrous?
In article , benwoodward.com
says... How can it be magnetic and not be ferrous? Iron Nickel Cobalt those are the three elements that have unpaired d electrons, and hence show ferromagnetism. Manganese can also be ferromagnetic, if diluted, for example, certain Mn:bronzes do this. Jim ================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ================================================== |
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Is tungsten carbide ferrous?
"jim rozen" wrote in message
... In article , benwoodward.com says... Thank you for your replies. TC is a ceramic then. Umm, I would say not a ceramic. There are many different definitions of ceramic but I think the best description of things like WC or TC would be a "cemented carbide." WC (what's TC?) is not a cemented carbide. It's a hard, high-strength "engineering" ceramic, just like silicon carbide, aluminum oxide, or titanium nitride. So are TiC, TiAlN, etc., etc. You can make a sintered carbide/metal composite out of them by mixing powders of the carbide(s) and the metal(s) and then pressing and sintering them into a solid mass. In fact, that's exactly what they do to make "carbide" tools. d8-) Ed Huntress |
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Is tungsten carbide ferrous?
benwoodward.com wrote:
How can it be magnetic and not be ferrous? Can it rust? Can it be welded to steel? Welded with steel? Also, if I quench harden 2016, why won't it cut carbide? Can tungsten carbide be quench hardened? Forged? I wonder. Nickel is magnetic. Once the Canadian Nickel was Nickel. I used them in lab to demonstrate the certain temp that the magnetic properties vanish. :-) another example : Lead Zirconate Titanate (PZT) Curie temp of 350 Curie temp - Ferromagnetic phase transitions - Curie Temp. Fe - 1033C - remember heat a rod of steel until it no longer attracts a magnet... Ni 627 C CrO2 380 C On and on. Rust is a slang term for Oxidation. Mostly ferric due to the color. item 4 is a catch all! " 1. Any of various powdery or scaly reddish-brown or reddish-yellow hydrated ferric oxides formed on iron and iron-containing materials by low-temperature oxidation in the presence of water. 2. Any of various metallic coatings, especially oxides, formed by corrosion. 3. A stain or coating resembling iron rust. 4. Deterioration, as of ability, resulting from inactivity or neglect. 5. Botany. 1. Rust fungus. 2. A plant disease caused by a rust fungus, characterized by reddish or brownish spots on leaves, stems, and other parts. 6. A strong brown. " Martin -- Martin Eastburn, Barbara Eastburn @ home at Lion's Lair with our computer NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder |
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Is tungsten carbide ferrous?
On Fri, 6 Feb 2004 11:44:40 -0600, "Tim Williams"
wrote: ,;"benwoodward.com" wrote in message e.com... ,; How can it be magnetic and not be ferrous? ,; ,;It can be ferromagnetic. Like the word phosphorescence, which now has ,;nearly nothing(?) to do with phosphorous (which has only a weak ,;phosphorescent effect anyway). ,; ,; Can it rust? ,; ,;Rust is a specific form of oxide, ferric (III) oxide, so it can only form ,;where there's iron. ,; ,; Can it be welded to steel? Welded with steel? ,; ,;Same thing? I doubt it, due to brittleness and differences in expansion ,;rate. But I wouldn't know. ,; ,; Also, if I quench harden 2016, why won't it cut carbide? ,; ,;Something can only be cut by something harder...obviously, carbide needs to ,;be cut with something a *lot* harder than steel. Like say, diamond. Unless ,;you reversed your statement, in which case, I don't know what the specs are ,;on cutting 2016 (aluminum? steel?) with carbide. ,; ,; Can tungsten carbide be quench hardened? Forged? Nope ,; ,;No. As far as I know it's a brittle material and can only be formed by ,;casting (since it melts upwards of 5200°F, um, ...no), sintering or abrasive ,;means of material removal (grinding, etc.). Being a definite chemical (WC) ,;I doubt it has different phases, so all a quench would do is crack it. It's ,;brittle, remember? Tungsten carbide is not necessarily WC. The carbon content can vary. Also what is generically referred to as "tungsten carbide" frequently has other carbides present e.g. tantalum carbide is present in some products. I don't know of any process in use where tungsten carbide is cast. We made a lot of it and it was all "cemented carbide" where cobalt is the usual binder. ,; ,;Now... I'll let someone like Ed H. correct me ,; ,;Tim |
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Is tungsten carbide ferrous?
"Don Wilkins" wrote in message
... On 6 Feb 2004 17:29:55 -0800, (benwoodward.com) wrote: ,;Thank you for your replies. TC is a ceramic then. I was totally ,;unaware just how alien to steel tc is. I'm classifying it under 'alien ,;technology successfully reverse engineered' and leaving it at that.:-) I certainly would not classify WC as a ceramic. The you would certainly be wrong, Don. WC is a ceramic. Tungsten-carbide tools are made of a powder-metallurgy composite of WC ceramic and metal powders. Ed Huntress |
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Is tungsten carbide ferrous?
On Sat, 07 Feb 2004 17:58:50 GMT, "Ed Huntress"
wrote: ,;"Don Wilkins" wrote in message ... ,; On 6 Feb 2004 17:29:55 -0800, ,; (benwoodward.com) wrote: ,; ,; ,;Thank you for your replies. TC is a ceramic then. I was totally ,; ,;unaware just how alien to steel tc is. I'm classifying it under 'alien ,; ,;technology successfully reverse engineered' and leaving it at that.:-) ,; ,; I certainly would not classify WC as a ceramic. ,; ,;The you would certainly be wrong, Don. WC is a ceramic. Tungsten-carbide ,;tools are made of a powder-metallurgy composite of WC ceramic and metal ,;powders. Well I disagree WC is not a ceramic. Take a look at a dictionary definition. We called them cermets and we probably made more of them than any other manufacturer. |
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Is tungsten carbide ferrous?
"Don Wilkins" wrote in message
... On Sat, 07 Feb 2004 17:58:50 GMT, "Ed Huntress" wrote: ,;"Don Wilkins" wrote in message ... ,; On 6 Feb 2004 17:29:55 -0800, ,; (benwoodward.com) wrote: ,; ,; ,;Thank you for your replies. TC is a ceramic then. I was totally ,; ,;unaware just how alien to steel tc is. I'm classifying it under 'alien ,; ,;technology successfully reverse engineered' and leaving it at that.:-) ,; ,; I certainly would not classify WC as a ceramic. ,; ,;The you would certainly be wrong, Don. WC is a ceramic. Tungsten-carbide ,;tools are made of a powder-metallurgy composite of WC ceramic and metal ,;powders. Well I disagree WC is not a ceramic. Take a look at a dictionary definition. HOkay, sometimes I lose track of the confusion that's propagated about this material, and the common uses of the term "ceramic," as well as the vague terms used in metallurgy to describe WC and TaC, which are interstitial carbides. On top of it all, the metalworking- and other industrial fields have added their own jargon. This is going to be one of my lengthy dissertations, so I'll apologize in advance and warn off anyone who doesn't really give a damn. On the other hand, they may find this interesting, because it's the result of research I did on the history of carbide tools in 1977, plus years of exposure as Materials Editor of American Machinist, and more recently as Tooling Editor of Machining magazine. You won't see it put together quite this way anywhere else, I believe. The term "ceramic" is old and vague as hell. It can include any non-metallic material, or compound of a metal and a non-metallic material, that's hard and brittle. You will sometimes see plain sand- and lime-putty mortar, which has a compression strength of only 75 - 350 psi, described as a "ceramic" in the building-restoration literature. This is not as ridiculous as it sounds; when lime putty (hydrated lime, Ca(OH2)) picks up CO2 from the atmosphere, it becomes CaCO3 -- limestone. That fills the bill: non-metallic and somewhat hard, somewhat brittle. As reconstituted limestone goes, lime mortar pretty lousy, but it's still within the definition. The definition of "ceramic" actually is that broad. Fine-clay dishware is generally described as "ceramic," as another example. There is no absolute technical definition, although engineers of advanced ceramics from around the world got together in 1993 and wrote one for their own use. It doesn't apply to anything we're interested in. It applies only to the newest, most advanced engineering ceramics. In Europe, engineers define plain glass as a ceramic. We're not interested in that definition, either. What we're interested in is something that will help us sort out the often contradictory uses of the term in industry. Here's a good one from Encyclopedia Britannica: "Industrial ceramics are commonly understood to be all industrially used materials that are inorganic, nonmetallic solids. Usually they are metal oxides (that is, compounds of metallic elements and oxygen), but many ceramics (especially advanced ceramics) are compounds of metallic elements and carbon, nitrogen, or sulfur." There's tungsten carbide for you: a metal (tungsten) compounded with carbon. It's hard, it's brittle, it's refractory, and it doesn't even melt like a metal. That's a ceramic. The bonding of W and C fit well within the more technical chemical definitions, which allow for both ionic and covalent bonds, plus various combinations thereof. WC is a particular type of ceramic: an interstitial carbide. Here's Britannica again: "Interstitial carbides are derived primarily from relatively large transition metals acting as a host lattice and the small carbon atoms occupying interstices of the close-packed metal atoms...Several have industrial importance, including tungsten carbide (WC) and tantalum carbide (TaC), which are used as high-speed cutting tools because of their extreme hardness and chemical inertness." Now for some background on the confusing, often contradictory uses of the terms. Back in the 1920s, some Germans came up with a way to make tools out of this hard stuff by mixing some WC powder and some cobalt powder, and then pressing and sintering them together into a composite material. It was NOT a compound. The carbide particles remained distinct in the composite. It was something like concrete in that regard. At about the same time, Philip McKenna (Kennametal) was experimenting with WC for cutting tools, too, trying to make them out of solid WC. You do this by taking straight WC powder and pressing it, and then sintering it at extremely high temperatures. I think WC sinters at around 4700 deg. F. Very difficult, and quite expensive (what do you make the pressing tools out of, for example?). He made the WC into billets and then sliced them into cutting tools with diamond saws. McKenna had some success but the result was too brittle and too expensive. It *was* capable of handling higher temperatures than the German stuff, and it was harder. But it was a no-go commercially. (Aside: the US Army is making big pieces of solid tungsten carbide again, much like McKenna's billets he made in the 1920s. Only the Army is using it for artillery shells.) So McKenna reverted to the German method, and these carbide/cobalt (and sometimes nickel) composites became available around the world, and were commonly called "cemented carbides." The cement, also known as the matrix, is the cobalt. First terminology problem: People got sloppy and started dropping the "cemented" part of "cemented carbide." It was just "carbide," or "tungsten carbide." Only it wasn't, really. It was some tungsten carbide mixed with some metal and sintered into a composite material. Second terminology problem: Metallurgists are more contrary than chemists, and they sometimes call tungsten carbide "metallike," or even a "metal." Chemists object. Metallurgists don't care. Machinists wind up confused. It's metallike, only it allows almost no slippage of crystals along slip planes: it has virtually no ductility, in other words. It behaves like a ceramic. It fits the definitions of ceramics that chemists and other scientists use. Metallurgists still don't care. They have their own little world. Third terminology problem: As newer ceramics came into play in the emerging world of "hard materials," they, too, got mixed with metal binders or matrices to form composites, and were given the name "cermets." Snappy, descriptive, and neat. However, somebody forgot about tungsten-carbide/cobalt composites. They're cermets, too. Marketing people in the cutting tool business didn't care. They had a snappy new name to apply to their new products, and they weren't going to let lowly old tungsten carbide horn in on the action. Machinists wind up confused. Tool companies don't care. So, does that help? There are no WC tools on the market that I know of. They're all cemented, metal-matrix composites made of ceramic WC, refractory metals, and sometimes odds and ends of other metals and ceramic compounds. A pure mass of WC is a pretty rare thing, and is not used for cutting tools today. It never was, except for some experiments. 'Sorry for the length. I didn't have time to write it shorter. g Ed Huntress |
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I knew there was a real reason for spending so much time reading this NG.
Nice post, Ed! Mike Eberlein Ed Huntress wrote: "Don Wilkins" wrote in message ... On Sat, 07 Feb 2004 17:58:50 GMT, "Ed Huntress" wrote: ,;"Don Wilkins" wrote in message ... ,; On 6 Feb 2004 17:29:55 -0800, ,; (benwoodward.com) wrote: ,; ,; ,;Thank you for your replies. TC is a ceramic then. I was totally ,; ,;unaware just how alien to steel tc is. I'm classifying it under 'alien ,; ,;technology successfully reverse engineered' and leaving it at that.:-) ,; ,; I certainly would not classify WC as a ceramic. ,; ,;The you would certainly be wrong, Don. WC is a ceramic. Tungsten-carbide ,;tools are made of a powder-metallurgy composite of WC ceramic and metal ,;powders. Well I disagree WC is not a ceramic. Take a look at a dictionary definition. HOkay, sometimes I lose track of the confusion that's propagated about this material, and the common uses of the term "ceramic," as well as the vague terms used in metallurgy to describe WC and TaC, which are interstitial carbides. On top of it all, the metalworking- and other industrial fields have added their own jargon. This is going to be one of my lengthy dissertations, so I'll apologize in advance and warn off anyone who doesn't really give a damn. On the other hand, they may find this interesting, because it's the result of research I did on the history of carbide tools in 1977, plus years of exposure as Materials Editor of American Machinist, and more recently as Tooling Editor of Machining magazine. You won't see it put together quite this way anywhere else, I believe. The term "ceramic" is old and vague as hell. It can include any non-metallic material, or compound of a metal and a non-metallic material, that's hard and brittle. You will sometimes see plain sand- and lime-putty mortar, which has a compression strength of only 75 - 350 psi, described as a "ceramic" in the building-restoration literature. This is not as ridiculous as it sounds; when lime putty (hydrated lime, Ca(OH2)) picks up CO2 from the atmosphere, it becomes CaCO3 -- limestone. That fills the bill: non-metallic and somewhat hard, somewhat brittle. As reconstituted limestone goes, lime mortar pretty lousy, but it's still within the definition. The definition of "ceramic" actually is that broad. Fine-clay dishware is generally described as "ceramic," as another example. There is no absolute technical definition, although engineers of advanced ceramics from around the world got together in 1993 and wrote one for their own use. It doesn't apply to anything we're interested in. It applies only to the newest, most advanced engineering ceramics. In Europe, engineers define plain glass as a ceramic. We're not interested in that definition, either. What we're interested in is something that will help us sort out the often contradictory uses of the term in industry. Here's a good one from Encyclopedia Britannica: "Industrial ceramics are commonly understood to be all industrially used materials that are inorganic, nonmetallic solids. Usually they are metal oxides (that is, compounds of metallic elements and oxygen), but many ceramics (especially advanced ceramics) are compounds of metallic elements and carbon, nitrogen, or sulfur." There's tungsten carbide for you: a metal (tungsten) compounded with carbon. It's hard, it's brittle, it's refractory, and it doesn't even melt like a metal. That's a ceramic. The bonding of W and C fit well within the more technical chemical definitions, which allow for both ionic and covalent bonds, plus various combinations thereof. WC is a particular type of ceramic: an interstitial carbide. Here's Britannica again: "Interstitial carbides are derived primarily from relatively large transition metals acting as a host lattice and the small carbon atoms occupying interstices of the close-packed metal atoms...Several have industrial importance, including tungsten carbide (WC) and tantalum carbide (TaC), which are used as high-speed cutting tools because of their extreme hardness and chemical inertness." Now for some background on the confusing, often contradictory uses of the terms. Back in the 1920s, some Germans came up with a way to make tools out of this hard stuff by mixing some WC powder and some cobalt powder, and then pressing and sintering them together into a composite material. It was NOT a compound. The carbide particles remained distinct in the composite. It was something like concrete in that regard. At about the same time, Philip McKenna (Kennametal) was experimenting with WC for cutting tools, too, trying to make them out of solid WC. You do this by taking straight WC powder and pressing it, and then sintering it at extremely high temperatures. I think WC sinters at around 4700 deg. F. Very difficult, and quite expensive (what do you make the pressing tools out of, for example?). He made the WC into billets and then sliced them into cutting tools with diamond saws. McKenna had some success but the result was too brittle and too expensive. It *was* capable of handling higher temperatures than the German stuff, and it was harder. But it was a no-go commercially. (Aside: the US Army is making big pieces of solid tungsten carbide again, much like McKenna's billets he made in the 1920s. Only the Army is using it for artillery shells.) So McKenna reverted to the German method, and these carbide/cobalt (and sometimes nickel) composites became available around the world, and were commonly called "cemented carbides." The cement, also known as the matrix, is the cobalt. First terminology problem: People got sloppy and started dropping the "cemented" part of "cemented carbide." It was just "carbide," or "tungsten carbide." Only it wasn't, really. It was some tungsten carbide mixed with some metal and sintered into a composite material. Second terminology problem: Metallurgists are more contrary than chemists, and they sometimes call tungsten carbide "metallike," or even a "metal." Chemists object. Metallurgists don't care. Machinists wind up confused. It's metallike, only it allows almost no slippage of crystals along slip planes: it has virtually no ductility, in other words. It behaves like a ceramic. It fits the definitions of ceramics that chemists and other scientists use. Metallurgists still don't care. They have their own little world. Third terminology problem: As newer ceramics came into play in the emerging world of "hard materials," they, too, got mixed with metal binders or matrices to form composites, and were given the name "cermets." Snappy, descriptive, and neat. However, somebody forgot about tungsten-carbide/cobalt composites. They're cermets, too. Marketing people in the cutting tool business didn't care. They had a snappy new name to apply to their new products, and they weren't going to let lowly old tungsten carbide horn in on the action. Machinists wind up confused. Tool companies don't care. So, does that help? There are no WC tools on the market that I know of. They're all cemented, metal-matrix composites made of ceramic WC, refractory metals, and sometimes odds and ends of other metals and ceramic compounds. A pure mass of WC is a pretty rare thing, and is not used for cutting tools today. It never was, except for some experiments. 'Sorry for the length. I didn't have time to write it shorter. g Ed Huntress |
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Is tungsten carbide ferrous?
On Sun, 08 Feb 2004 07:49:38 GMT, "Ed Huntress"
wrote: ,;"Don Wilkins" wrote in message ... ,; On Sat, 07 Feb 2004 17:58:50 GMT, "Ed Huntress" ,; wrote: ,; ,; ,;"Don Wilkins" wrote in message ,; ... ,; ,; On 6 Feb 2004 17:29:55 -0800, ,; ,; (benwoodward.com) wrote: ,; ,; ,; ,; ,;Thank you for your replies. TC is a ceramic then. I was totally ,; ,; ,;unaware just how alien to steel tc is. I'm classifying it under ,;'alien ,; ,; ,;technology successfully reverse engineered' and leaving it at ,;that.:-) ,; ,; ,; ,; I certainly would not classify WC as a ceramic. ,; ,; ,; ,;The you would certainly be wrong, Don. WC is a ceramic. ,;Tungsten-carbide ,; ,;tools are made of a powder-metallurgy composite of WC ceramic and metal ,; ,;powders. ,; ,; Well I disagree WC is not a ceramic. ,; ,; Take a look at a dictionary definition. ,; ,;HOkay, sometimes I lose track of the confusion that's propagated about this ,;material, and the common uses of the term "ceramic," as well as the vague ,;terms used in metallurgy to describe WC and TaC, which are interstitial ,;carbides. On top of it all, the metalworking- and other industrial fields ,;have added their own jargon. This is going to be one of my lengthy ,;dissertations, so I'll apologize in advance and warn off anyone who doesn't ,;really give a damn. On the other hand, they may find this interesting, ,;because it's the result of research I did on the history of carbide tools in ,;1977, plus years of exposure as Materials Editor of American Machinist, and ,;more recently as Tooling Editor of Machining magazine. You won't see it put ,;together quite this way anywhere else, I believe. I am going to delete some of your material here in the interest of length. Your discussion covers most of the vagueness of the term "ceramic" and I doubt if we would have any disagreement if we had the opportunity to spend a couple hours in a face to face discussion of the topic. I am a research chemist and spent the first 15 years of my career in the metallurgy research laboratory of a large corporation. What the hell it was the General Electric Research Laboratory. The second 18 years I was at the same facility and although still dealing with the metallurgists and ceramists I also had to contend with a bunch of organic chemists. Ceramics was my second major in a PH.D. program at the University of Illinois. We probably made more cemented carbides than any other company and at the time I started we were in the midst of developing the production of synthetic diamonds. None of cemented carbide research or the synthetic diamond research was done in our Ceramics Laboratory. Yes the term is vague, widely used and widely miss-used. The following information on ceramics is blatantly copied in part from the "Encyclopedia of Chemistry" edited by G.L.Clark a well-known chemist and one of my U of I professors. Parts of the stuff below was authored by A.I. Andrews head of the Ceramics Department at the U of I and one of my committee members. **An all-embracing definition is rather difficult because it includes what appears by a cursory examination to cover widely diverse areas. A recent committee of the American Ceramic Society defined ceramics to include those industries which manufacture products by the action of heat on raw materials, most of which are of an earthy nature, in which the chemical element silicon together with its oxide and complex compounds known as silicates occupy a predominant position. They go on to say "It is much easier to understand the scope of the ceramic industry by a consideration of specific products. It may be divided into seven major areas:" For brevity's sake the areas are listed here by title only without expansion...Structural clay products, Whitewares, All varieties of glass products, Porcelain enamel products, Refractories, Cemented materials such as Portland cement, & Abrasive materials such as alumina, silicon carbide. *** Now I can see a quick Ah Hah from Ed but would hasten to point out that although cemented WC certainly fits in some of those categories it is not specifically mentioned in the definitions. In addition Cermets, Refractorys, & Abrasives are covered separately in the Encyclopedia. My problem with calling WC a ceramic probably comes from the viewpoint of a chemist tainted by a long association with a bevy of ceramists and metallurgists. Here is my reservation in a nutshell...Would one call the following compounds ceramics: iron carbide, aluminum carbide, iron oxide, calcium oxide, calcium carbide, silicon dioxide, molybdenum sulfide, etc. If it is a single compound I would be very hesitant to call it a ceramic. So by my definition one needs two or more compounds along with some interaction so as to not have a simple mixture to get a ceramic. WC (to me) is a chemical compound (it is a carbide) as is e.g. SiO2 an oxide and not a ceramic. Quartz might give me some hemming and hawing as one could consider it a glass which sort of puts it in the ceramic category. Cemented carbides fall very nicely into the category of "Cermets" which is from my point of view a better and more descriptive and well recognized category. If the question had been "cemented WC" I probably wouldn't have made the same comment but when the topic was WC it created all sorts of misgivings to let that go by as a ceramic. Actually I am crotchety enough in my old age so I still consider cemented carbides as cermets not ceramics but how one classifies them probably depends a great deal on one's background. To repeat... Ed's excellent dissertation is deleted for brevity. It certainly exhibits why there are differences of opinions even by those actively working in the field which I haven't done for almost 18 years now. ,; ,; ,;'Sorry for the length. I didn't have time to write it shorter. g No need to apologize. Your points are well taken,interesting, & instructive. Don |
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Is tungsten carbide ferrous?
In article , Ed Huntress
says... "Industrial ceramics are commonly understood to be all industrially used materials that are inorganic, nonmetallic solids. Usually they are metal oxides (that is, compounds of metallic elements and oxygen), but many ceramics (especially advanced ceramics) are compounds of metallic elements and carbon, nitrogen, or sulfur." This portion of your excellent discussion is what does it for me, the fact that cemented carbides are composed to some large degree of cobalt metal means that I would tend to shy away from the 'ceramic' label. Though I have to agree that the issue is a confusing one - here the thing's name really depends on who is doing the describing: physicist, ceramist, chemist, machinist, etc. Jim ================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ================================================== |
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Is tungsten carbide ferrous?
"jim rozen" wrote in message
... In article , Ed Huntress says... "Industrial ceramics are commonly understood to be all industrially used materials that are inorganic, nonmetallic solids. Usually they are metal oxides (that is, compounds of metallic elements and oxygen), but many ceramics (especially advanced ceramics) are compounds of metallic elements and carbon, nitrogen, or sulfur." This portion of your excellent discussion is what does it for me, the fact that cemented carbides are composed to some large degree of cobalt metal means that I would tend to shy away from the 'ceramic' label. So would I. Cemented carbide cutting tools are NOT ceramics. They *contain* ceramics, especially WC and TaC. That was my main point. g Though I have to agree that the issue is a confusing one - here the thing's name really depends on who is doing the describing: physicist, ceramist, chemist, machinist, etc. Another good point. Note Don's hesitations, based on the definitions he accepts as a chemist. The problem is, chemists don't have a hold on the definitions. They have never bothered to make a precise, technical definition of ceramics, because it's not really a technical term. Engineers of advanced ceramics have created a definition for their own use, back in 1993, as I mentioned. But they freely acknowledge that the definition is only for their purposes, to help avoid confusion within their own field. They're not trying to convince the world that they have the "correct" definition. Ed Huntress |
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Is tungsten carbide ferrous?
Both great dissertations. Thanks for another interesting discussion.
Tim (TOP-posting for brevity) -- "That's for the courts to decide." - Homer Simpson Website @ http://webpages.charter.net/dawill/tmoranwms "Don Wilkins" wrote in message ... On Sun, 08 Feb 2004 07:49:38 GMT, "Ed Huntress" wrote: ,;"Don Wilkins" wrote in message ... ,; On Sat, 07 Feb 2004 17:58:50 GMT, "Ed Huntress" ,; wrote: ,; ,; ,;"Don Wilkins" wrote in message ,; ... ,; ,; On 6 Feb 2004 17:29:55 -0800, ,; ,; (benwoodward.com) wrote: ,; ,; ,; ,; ,;Thank you for your replies. TC is a ceramic then. I was totally ,; ,; ,;unaware just how alien to steel tc is. I'm classifying it under ,;'alien ,; ,; ,;technology successfully reverse engineered' and leaving it at ,;that.:-) ,; ,; ,; ,; I certainly would not classify WC as a ceramic. ,; ,; ,; ,;The you would certainly be wrong, Don. WC is a ceramic. ,;Tungsten-carbide ,; ,;tools are made of a powder-metallurgy composite of WC ceramic and metal ,; ,;powders. ,; ,; Well I disagree WC is not a ceramic. ,; ,; Take a look at a dictionary definition. ,; ,;HOkay, sometimes I lose track of the confusion that's propagated about this ,;material, and the common uses of the term "ceramic," as well as the vague ,;terms used in metallurgy to describe WC and TaC, which are interstitial ,;carbides. On top of it all, the metalworking- and other industrial fields ,;have added their own jargon. This is going to be one of my lengthy ,;dissertations, so I'll apologize in advance and warn off anyone who doesn't ,;really give a damn. On the other hand, they may find this interesting, ,;because it's the result of research I did on the history of carbide tools in ,;1977, plus years of exposure as Materials Editor of American Machinist, and ,;more recently as Tooling Editor of Machining magazine. You won't see it put ,;together quite this way anywhere else, I believe. I am going to delete some of your material here in the interest of length. Your discussion covers most of the vagueness of the term "ceramic" and I doubt if we would have any disagreement if we had the opportunity to spend a couple hours in a face to face discussion of the topic. I am a research chemist and spent the first 15 years of my career in the metallurgy research laboratory of a large corporation. What the hell it was the General Electric Research Laboratory. The second 18 years I was at the same facility and although still dealing with the metallurgists and ceramists I also had to contend with a bunch of organic chemists. Ceramics was my second major in a PH.D. program at the University of Illinois. We probably made more cemented carbides than any other company and at the time I started we were in the midst of developing the production of synthetic diamonds. None of cemented carbide research or the synthetic diamond research was done in our Ceramics Laboratory. Yes the term is vague, widely used and widely miss-used. The following information on ceramics is blatantly copied in part from the "Encyclopedia of Chemistry" edited by G.L.Clark a well-known chemist and one of my U of I professors. Parts of the stuff below was authored by A.I. Andrews head of the Ceramics Department at the U of I and one of my committee members. **An all-embracing definition is rather difficult because it includes what appears by a cursory examination to cover widely diverse areas. A recent committee of the American Ceramic Society defined ceramics to include those industries which manufacture products by the action of heat on raw materials, most of which are of an earthy nature, in which the chemical element silicon together with its oxide and complex compounds known as silicates occupy a predominant position. They go on to say "It is much easier to understand the scope of the ceramic industry by a consideration of specific products. It may be divided into seven major areas:" For brevity's sake the areas are listed here by title only without expansion...Structural clay products, Whitewares, All varieties of glass products, Porcelain enamel products, Refractories, Cemented materials such as Portland cement, & Abrasive materials such as alumina, silicon carbide. *** Now I can see a quick Ah Hah from Ed but would hasten to point out that although cemented WC certainly fits in some of those categories it is not specifically mentioned in the definitions. In addition Cermets, Refractorys, & Abrasives are covered separately in the Encyclopedia. My problem with calling WC a ceramic probably comes from the viewpoint of a chemist tainted by a long association with a bevy of ceramists and metallurgists. Here is my reservation in a nutshell...Would one call the following compounds ceramics: iron carbide, aluminum carbide, iron oxide, calcium oxide, calcium carbide, silicon dioxide, molybdenum sulfide, etc. If it is a single compound I would be very hesitant to call it a ceramic. So by my definition one needs two or more compounds along with some interaction so as to not have a simple mixture to get a ceramic. WC (to me) is a chemical compound (it is a carbide) as is e.g. SiO2 an oxide and not a ceramic. Quartz might give me some hemming and hawing as one could consider it a glass which sort of puts it in the ceramic category. Cemented carbides fall very nicely into the category of "Cermets" which is from my point of view a better and more descriptive and well recognized category. If the question had been "cemented WC" I probably wouldn't have made the same comment but when the topic was WC it created all sorts of misgivings to let that go by as a ceramic. Actually I am crotchety enough in my old age so I still consider cemented carbides as cermets not ceramics but how one classifies them probably depends a great deal on one's background. To repeat... Ed's excellent dissertation is deleted for brevity. It certainly exhibits why there are differences of opinions even by those actively working in the field which I haven't done for almost 18 years now. ,; ,; ,;'Sorry for the length. I didn't have time to write it shorter. g No need to apologize. Your points are well taken,interesting, & instructive. Don |
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Is tungsten carbide ferrous?
"Don Wilkins" wrote in message
... I am going to delete some of your material here in the interest of length. Your discussion covers most of the vagueness of the term "ceramic" and I doubt if we would have any disagreement if we had the opportunity to spend a couple hours in a face to face discussion of the topic. I am a research chemist and spent the first 15 years of my career in the metallurgy research laboratory of a large corporation. What the hell it was the General Electric Research Laboratory. The second 18 years I was at the same facility and although still dealing with the metallurgists and ceramists I also had to contend with a bunch of organic chemists. Ceramics was my second major in a PH.D. program at the University of Illinois. We probably made more cemented carbides than any other company and at the time I started we were in the midst of developing the production of synthetic diamonds. None of cemented carbide research or the synthetic diamond research was done in our Ceramics Laboratory. You'll note, however, that handbook descriptions of ceramics sometimes note that diamond technically falls within their definitions of "ceramics." It's not included in the common explanations because of convention, not because of some technical exclusion. In the US, it's conventional to include only compounds among the ceramics. In Europe, that's not necessarily so. Again, it's more a matter of technical conventions. Yes the term is vague, widely used and widely miss-used. The following information on ceramics is blatantly copied in part from the "Encyclopedia of Chemistry" edited by G.L.Clark a well-known chemist and one of my U of I professors. Parts of the stuff below was authored by A.I. Andrews head of the Ceramics Department at the U of I and one of my committee members. **An all-embracing definition is rather difficult because it includes what appears by a cursory examination to cover widely diverse areas. A recent committee of the American Ceramic Society defined ceramics to include those industries which manufacture products by the action of heat on raw materials, most of which are of an earthy nature, in which the chemical element silicon together with its oxide and complex compounds known as silicates occupy a predominant position. They go on to say "It is much easier to understand the scope of the ceramic industry by a consideration of specific products. It may be divided into seven major areas:" For brevity's sake the areas are listed here by title only without expansion...Structural clay products, Whitewares, All varieties of glass products, Porcelain enamel products, Refractories, Cemented materials such as Portland cement, & Abrasive materials such as alumina, silicon carbide. *** Now I can see a quick Ah Hah from Ed but would hasten to point out that although cemented WC certainly fits in some of those categories it is not specifically mentioned in the definitions. In addition Cermets, Refractorys, & Abrasives are covered separately in the Encyclopedia. However, that's just industry convention and internal definitions. For example, WC is listed as a ceramic in the NIST ceramics database. My problem with calling WC a ceramic probably comes from the viewpoint of a chemist tainted by a long association with a bevy of ceramists and metallurgists. Here is my reservation in a nutshell...Would one call the following compounds ceramics: iron carbide, aluminum carbide, iron oxide, calcium oxide, calcium carbide, silicon dioxide, molybdenum sulfide, etc. If it is a single compound I would be very hesitant to call it a ceramic. So by my definition one needs two or more compounds along with some interaction so as to not have a simple mixture to get a ceramic. WC (to me) is a chemical compound (it is a carbide) as is e.g. SiO2 an oxide and not a ceramic. Quartz might give me some hemming and hawing as one could consider it a glass which sort of puts it in the ceramic category. Again, conventions, not technical exclusions. For example, your "single compound" [I assume you mean "two-component" compound] definition runs into a big problem with the fact that the overwhelming volume of engineering ceramics (sometimes called "technical ceramics," especially in Europe) is two-component compounds: silicon nitride; silicon carbide; aluminum oxide; and zirconium oxide. Together, that group is the one usually called the conventional "engineering ceramics" in engineering. The definitional problem you're raising is similar to the one that those engineers who got together in 1993, as I mentioned, were facing. The newest, highest-performing engineering ceramics are mostly complex compounds. They're used primarily in electronics and in aerospace. However, two-component ceramics are the dominant ones in industry, and no one that I know of would reject, say, silicon nitride or zirconium oxide as major industrial ceramics. As for iron carbide, iron oxide, etc.: iron carbide most definitely is considered a ceramic carbide in engineering. Iron carbide, along with chromium carbide and vanadium carbide (the dominant one in terms of performance) are the ceramic carbides that make up a percentage of the better high-speed steels. In the very high-performance HSS, such as CPM Rex 121, they make up over 30% of the total mix, and they're very important to the materials' properties. Iron oxide is one that tests the definitions. Red rust (Fe2O3) meets some peoples' definitions but not others'. It would be interesting to see what its properties were if it were compacted and sintered. Black rust, on the other hand (Fe3O4), the tenacious stuff that often tends to hang on when we strip red rust off of steel with phosphoric acid, is sometimes called the "ceramic form" of iron oxide. Now, since you're a chemist, I should say that I'm aware there are two different forms of Fe3O4, and that only one of them meets this definition (magnetite). But the point is that some iron oxides exhibit ceramic properties, and are justly called "ceramic" by the common definitions. Cemented carbides fall very nicely into the category of "Cermets" which is from my point of view a better and more descriptive and well recognized category. Cemented carbides, definitely. But "cermet" is a marketing term, not a technical term. If the question had been "cemented WC" I probably wouldn't have made the same comment but when the topic was WC it created all sorts of misgivings to let that go by as a ceramic. Actually I am crotchety enough in my old age so I still consider cemented carbides as cermets not ceramics but how one classifies them probably depends a great deal on one's background. You're right, they definitely are cermets, or metal-matrix ceramic/metal composites, if you want to get precise. They most definitely are NOT ceramics! They CONTAIN ceramics, in a mechanical mixture of metal and ceramic powders that is sintered into a solid mass. Their properties fall somewhere between the properties of ceramics and metals. But that's due to the mechanical mixture, and their properties adhere to the law of mixtures, as it's known in materials science. But "carbide" tools, or "WC" tools, are neither carbides, nor tungsten carbide, nor ceramics. Let's make sure we're clear on this: WC is a ceramic. Tools are not made of pure WC, any more than a "fiberglass" Corvette body is made of pure glass. Cemented carbides are metal-matrix composites that *contain* WC. I hope we have agreement at least on the point that "carbide" tools are not ceramics. They're mixtures of ceramics and metal(s). To repeat... Ed's excellent dissertation is deleted for brevity. It certainly exhibits why there are differences of opinions even by those actively working in the field which I haven't done for almost 18 years now. I'm sure your definitions are considered the more useful ones in the technical end of your former business, Don. That's perhaps a good chemist's definition. But it is a minority position within industry. The mainstream definition *within engineering* doesn't think much of including hardened lime putty among ceramics, but the people who make decorative ceramics, and who call themselves ceramicists, probably would disagree. The word "ceramics" comes from the Greek word for "potter's clay." A lot of different people, in diverse arts and industries, believe their definition is the correct one. g But within mechanical engineering and the closely related arms of materials science, tungsten carbide, silicon carbide, tantalum carbide, vanadium carbide, aluminum oxide, etc. are all mainstream engineering ceramics. It *is* a matter of definition. But consider the relevant issues in mechanical engineering, or most other aspects of engineering: these materials are all hard as hell; they non-ductile; they're highly refractory; they're compounds of metals (iron, aluminum tungsten) or metalloids (boron, silicon) and non-metals (oxygen, carbon, nitrogen, etc.); and they're generally quite inert. Those are the properties that are relevant, and they're the ones that fit the mainstream, engineering definition of ceramics -- including tungsten carbide. The fact that some include these materials in their definitions of ceramics and others do not is a matter of convention and tradition more than of some chemical definition. And that's true because there is no precise chemical definition of a ceramic. -- Ed Huntress (remove "3" from email address for email reply) |
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"mikee" wrote in message
... I knew there was a real reason for spending so much time reading this NG. Nice post, Ed! Mike Eberlein Thanks, Mike. I used to get paid for that kind of stuff. Now it's just a bad habit. g Ed Huntress |
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On 8 Feb 2004 08:30:48 -0800, jim rozen
wrote: ,;In article , Ed Huntress ,;says... ,; ,;"Industrial ceramics are commonly understood to be all industrially used ,;materials that are inorganic, nonmetallic solids. Usually they are metal ,;oxides (that is, compounds of metallic elements and oxygen), but many ,;ceramics (especially advanced ceramics) are compounds of metallic elements ,;and carbon, nitrogen, or sulfur." ,; ,;This portion of your excellent discussion is what does it for me, ,;the fact that cemented carbides are composed to some large degree ,;of cobalt metal means that I would tend to shy away from the ,;'ceramic' label. Though I have to agree that the issue is a ,;confusing one - here the thing's name really depends on who ,;is doing the describing: physicist, ceramist, chemist, machinist, ,;etc. Actually the cobalt content of cemented tungsten carbide is small compared to the WC and other carbides. The reason cobalt is used is that it wets the surface of WC and doesn't run wild dissolving the carbide. Nickel or iron or a lot of other elements would be cheaper. How you label these materials certainly will depend on your background. I thought Ed and I might agree but it ain't gonna happen. That makes no difference because we are both correct in the environment in which we work. |
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"Don Wilkins" wrote in message
... On 8 Feb 2004 08:30:48 -0800, jim rozen wrote: ,;In article , Ed Huntress ,;says... ,; ,;"Industrial ceramics are commonly understood to be all industrially used ,;materials that are inorganic, nonmetallic solids. Usually they are metal ,;oxides (that is, compounds of metallic elements and oxygen), but many ,;ceramics (especially advanced ceramics) are compounds of metallic elements ,;and carbon, nitrogen, or sulfur." ,; ,;This portion of your excellent discussion is what does it for me, ,;the fact that cemented carbides are composed to some large degree ,;of cobalt metal means that I would tend to shy away from the ,;'ceramic' label. Though I have to agree that the issue is a ,;confusing one - here the thing's name really depends on who ,;is doing the describing: physicist, ceramist, chemist, machinist, ,;etc. Actually the cobalt content of cemented tungsten carbide is small compared to the WC and other carbides. The reason cobalt is used is that it wets the surface of WC and doesn't run wild dissolving the carbide. Nickel or iron or a lot of other elements would be cheaper. How you label these materials certainly will depend on your background. I thought Ed and I might agree but it ain't gonna happen. That makes no difference because we are both correct in the environment in which we work. Oh, I don't think we disagree, Don. I'm just being contrary. g In trying to clarify something like this it's often more important to identify the points of disagreement than those of agreement. I don't write to explain things to people like you, who know more about the chemistry of it than I'll ever know. I write to make as clear as I can the things that are relevant and distinctive to the machinists and people with an applications-engineering interest in materials. So don't think we really disagree. My point there was that your understanding of ceramics is based on a chemist's needs and understanding, which is at the opposite pole from a ceramicist's needs and understanding. People who do metalworking with these materials are somewhere in the middle of those two extremes. Tungsten carbide is a misunderstood material, lost in jargon and convention within the metalworking trades. I've tried to deal with that and explain it to a magazine audience for roughly 30 years, although not quite in the terms we've been using here. Having your POV on it is extremely helpful -- for the contrasts more than the similarities, actually. One could make a case that it's a lack of confrontation between the different views on this subject that have helped to muddy the waters over the last 80 years. Now, if we had a potter here on the NG, we'd really be able to put some perspective on it. g Ed Huntress |
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In article ,
Tim Williams wrote: Both great dissertations. Thanks for another interesting discussion. I agree with this. Tim (TOP-posting for brevity) However -- *why* did you quote the whole thing yet again? You did not need to quote it all -- it was all out there in the newsgroup still, and any *reasonable* newsreader could have followed a link back from your article. Instead, you quoted 143 lines, with no need at all. That does not qualify as "brevity" in my book. *This* is why people object to top posting. Once someone does that, they seem to feel no need to trim excess quoted material. If you *must* top-post -- *please* trim most of the quoted material. Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
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"DoN. Nichols" wrote in message
... However -- *why* did you quote the whole thing yet again? You did not need to quote it all -- If it weren't quoted some people might be confused as to what I'm replying to. Instead, you quoted 143 lines, with no need at all. That does not qualify as "brevity" in my book. Far better than putting my one-liner at the very bottom. If you *must* top-post -- *please* trim most of the quoted material. I usually do...just lazy this time. Tim -- "That's for the courts to decide." - Homer Simpson Website @ http://webpages.charter.net/dawill/tmoranwms |
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On Mon, 09 Feb 2004 01:07:15 GMT, Ed Huntress
wrote: Now, if we had a potter here on the NG, we'd really be able to put some perspective on it. g Ed Huntress Or maybe the guy we heard about who was supposedly caught stealing ceramic tool bits back when they were still quite a new thing. Supposedly when they checked his house, they found that he'd tiled his bathroom floor with them. Probably an urban myth, but quite a story, especially when they used to cost about 10X what they do today. Karl Pearson -- Delete 1 from address - munged to avoid spam and worse |
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"Karl Pearson" wrote in message
news  On Mon, 09 Feb 2004 01:07:15 GMT, Ed Huntress wrote: Now, if we had a potter here on the NG, we'd really be able to put some perspective on it. g Ed Huntress Or maybe the guy we heard about who was supposedly caught stealing ceramic tool bits back when they were still quite a new thing. Supposedly when they checked his house, they found that he'd tiled his bathroom floor with them. Probably an urban myth, but quite a story, especially when they used to cost about 10X what they do today. Ouch! I hope they were negative-rake. Ed Huntress |
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Tim Williams wrote:
: Can it be welded to steel? Welded with steel? --I'd say definitely yes; didja ever touch a tungsten electrode into the puddle while welding steel? Coats just dandy and you have to grind it off! :-) -- "Steamboat Ed" Haas : Time flies like an arrow Hacking the Trailing Edge! : Fruit flies like a banana... http://www.nmpproducts.com/intro.htm ---Decks a-wash in a sea of words--- |
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In article , steamer says...
Tim Williams wrote: : Can it be welded to steel? Welded with steel? --I'd say definitely yes; didja ever touch a tungsten electrode into the puddle while welding steel? Coats just dandy and you have to grind it off! :-) Hmm. I would say that tungsten =/ tungsten carbide... Jim ================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ================================================== |
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