I see this allot of adds for powdered metal endmills , what is this different than carbide ? a
17 years ago
I see this allot of adds for powdered metal endmills , what is this different than carbide ? a
Here is an interesting factoid: The modulus of elasticity (stiffness) for steel is about 30 million PSI and is not effected by its hardness. The hardest pieces of HSS will defect the same amount as the softest paper clip, given the same shape, so long as you stay within the elastic limits of the material. The difference between the two is the yield point. The soft steel reaches a point and yields (takes a permanent set) instead of offering more resistance against a force where the hard steel will continue to deflect in a linear correlation to applied force until it fails (at a relatively high amount of deflection). The moral to this story is that, so long as you're not subjecting steel to forces that cause a permanent deformation or failure, they are all the same in stiffness, regardless of their hardness and (mostly) their alloy composition. There is nothing you can do to steel to make it stiffer. Period. Sorry.
Which brings me to why I use carbide in difficult length to diameter situations. Yes, carbide does not hold up well to chatter, but HSS will chatter worse, all else equal. If you're chattering, you're cutting too deep, or feeding too slow, or turning too fast. If you're experiencing chatter in a cut, and you want the cutter to survive, use HSS. If you want you part to not be covered in chatter, use carbide and modify your program to eliminate chatter. I'd love to get the input of someone like BB or BD who know more about this subject than I do to get their opinion.
Which brings me to this question (and the point of this dissertation) How does the flex mod of powdered metal compare to carbide? Is it basically an iron alloy, limited to 30 million PSI, or is it something stiffer?
Congrats to Polymer Man. You fit into my 100 to 1 theory. It is surprising how few people know you can't change stiffness (modulus of elasticity) by heat treat or alloy. I worked in an aircraft mechanical testing lab for five years and must have done 50,000 tensile tests and still had no knowledge of this principle. I recently brought it up to a very veteran tool steel salesman, and an arguement instantly started. I have a carpenter tool steel book that shows clearly the tests that proved my point. All I got was a dirty look and probably lost any discounts I may have got from him!
P.S. 100 to 1 is probably being way to nice.
"It is surprising how few people know you can't change stiffness (modulus of elasticity) by heat treat or alloy."
Thanks Dixon, glad to make your list.
Yeah, I've had similar conversations with people about the use of 4130 in a race car. Yeah, it is stronger, but it can't effect handing (compared to plain 'ol HRPO) because it isn't any stiffer. Oh, and parts made of 6-4 titanium may be stronger and lighter, but they'll only be half as stiff as old fashioned FE.
I doubt the additional control over the metallurgical properties and grain structure possible in PM tooling will change the stiffness. Those characteristics are what you're modifying in carbon steel through alloying and heat treatment, and it has no effect in conventional steel, what would make PM special if it is also FE based?
Cutter flexibility causes me all kind of problems when the length gets to be 8 or 12 times the diameter. In that situation I'll use carbide, but not for its additional hardness or high heat performance, but for rigidity.
I wish BD or BB would comment on their experiences, where they may use carbide, but not run it up fast but because it doesn't deflect as much.
Here are some factoids somewhat related to your points: Figures are rough estimates.
Steel density around 7.8 (g/cc), modulus of elasticity 30,000,000 PSI
Aluminum density around 2.7 (g/cc), modulus of elasticity 10,000,000 PSI
Titanium density around 4.5 (g/cc), modulus of elasticity 15,000,000 PSI
Tungsten Carbide density around 15 (g/cc), modulus of elasticity65,000,000 - 90,000,000 PSI
Summarized: Aluminum has about 1/3 the density of steel and has a modulus 1/3 as great. Titanium has about 1/2 the density of steel, and has a modulus of 1/2 that of steel Carbide has a density about double than of steel, and has a modulus over twice as much as steel.
But density certainly isn't the full story since the density of Lead is around 11 (g/cc), and its modulus of elasticity is only 2,500,000 PSI.
Actually, probably everyone has used long carbide cutters mainly to resist deflection. We were just cutting a thru pocket in a 12" cubical block today (half-way through from either side), with a 1" dia. finishing carbide cutter 6"-7" long and running it at about 450 RPM and15 IPM around the inner perimeter.
What makes you think that density has anything at all to do with it?
Natural Diamond: 102,000 - 174,000 ksi Density 3.51 - 3.52 g/cc
Cast Uranium: 27,600 ksi Density: 19.07 g/cc
I was just making an observation "that in those three cases" the modulus of elasticity follows the density of the material. Do you doubt that factoid? Did I ever state that the density was a necessary sole causative factor? No, I did not. In fact I also wrote the following to dissuade anyone of coming to that conclusion:
"But density certainly isn't the full story since the density of Lead is around 11 (g/cc), and its modulus of elasticity is only 2,500,000 PSI."
But you seem to have accidentally edited that comment of mine out of your reply. I'm sure you wouldn't stoop to using such an obvious trolling tactic of editing other's comments to make it appear they said something they didn't, now would you.
BTW, since when is Diamond a metal? The subject was metals and their relative "stiffness". Uranium is indeed very dense and it's modulus is close to steel, but I'd venture to guess that few machinists have worked with that particular metal. But most everyone can identify with the properties of lead as being simultaneously dense AND soft, so I think it's a better example for most machinists.
So you think that Carbides are metals? How about Ceramics?
You don't think Tungsten Carbide is a metal? LMAO!
I never mentioned ceramics in this thread.
Umm .. It's not? HTH. What do you think that metals are?
Carbides were mentioned and you just mentioned Tungsten Carbide (Subcategory: Carbide; Ceramic), which has an Electrical Resistivity of 5.3e-005 to 8e-005 ohm-cm .
With that question mark, I can't tell if you're asking or telling.
========================================================= Tungsten, symbol W (from the earlier name, wolfram), metallic element that has the highest melting point of any metal.
"Tungsten," Microsoft® Encarta® Encyclopedia 2000. © 1993-1999 Microsoft Corporation. All rights reserved. =========================================================
I think we have established beyond a reasonable doubt that Tungsten is a metal.
========================================================= Carbides, compounds of carbon with metals or metalloids.
Important metallic carbides include iron carbide, or cementite, the hardening constituent in steel; tungsten carbide, from which are made hard tools for the machining of tough metals;
"Carbides," Microsoft® Encarta® Encyclopedia 2000. © 1993-1999 Microsoft Corporation. All rights reserved. =========================================================
========================================================== Cobalt (element), symbol Co, silvery-white, magnetic, metallic element used chiefly for making alloys. An alloy with steel known as cobalt steel is used for making permanent magnets. With tungsten carbide, cobalt forms Carboloy, a hard material used for cutting and machining steel;
"Cobalt (element)," Microsoft® Encarta® Encyclopedia 2000. © 1993-1999 Microsoft Corporation. All rights reserved. ==========================================================
Bottom line, Tungsten carbide is a chemical compound made up of Tungsten metal, carbon, and the metal Cobalt as a binder.
I never considered it a metal. I know better. The "LMAO" seems to be on you .
Up early? Too late? Confused? "You don't think Tungsten Carbide is a metal? LMAO!"
But it's NOT a metal .
Who cares what you considered, or didn't consider something? Opinions aren't facts, let's see some facts/evidence.
Perhaps, perhaps not. LOL
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.
Well let's just take a look at the properties of metals.
============================================================== 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.
"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
Thermal Conductivity - Tungsten carbide is in the range of twice that of tool steel and carbon steel.
Electrical Conductivity - Tungsten carbide is in the same range as tool steel and carbon steel. ==============================================================
If carbide end mills weren't electrically conductive they wouldn't make my LED conductive tool length offsetting tool work, but they do.
Tungsten carbide cutting tools sure seem to fit the criteria for metals given above. If you have some evidence to the contrary (that's EVIDENCE now - not opinion), let's hear it.
You are confused .
And you opine is that Carbides are metals. LOL ....
You don't seem to know, eh? Lint attack again?
No "perhaps" about it, BB. I think Wick got you yet again.
What part of "CARBIDE" was unclear?
WHY? Think you'll find either Carbides or Tungsten Carbide there?
Good for you. You can copy & paste stuff. So can jb.
NOW it's "Tungsten carbide tooling" ..... Rocks are opaque too so I suppose that you think that they are metals too ... yet Sodium is soft ...
steel =~ Thermal Conductivity 51.9 W/m-K 360 BTU-in/hr-ft²-°F
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
So Diamond is a metal too?
It's not my fault that you are unable to support your claim, and seem to be in a snit over it.
Heh, let's call it a working hypothesis, which can change when convincing contradicting evidence is presented.
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.
I'm not the one that is having trouble backing up his claim.
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."
I thought I'd find some general properties of metals with which we could compare the properties of Tungsten Carbide, and I did.
IMO, copying from credible sources trumps unsupported conjecture and WAG's any day.
Of course it's Tungsten carbide tooling, what do you think the discussion was about, Carbide Bucky Balls?
Do all rocks have good electrical and thermal conductivity? NO! Do all rocks have a crystalline structure? NO! Do all rocks have a luster when polished? NO!
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
Is Diamond a good conductor of electricity? (Probably the most important aspect of metals and their resultant metallic bonds) NO!
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.
So the bottom line so far is that you HAVE NOT presented any factual evidence that Tungsten carbide is NOT a metal. But yet Tungsten carbide seems to correlate very well with the properties of metals listed from Encarta Encyclopedia.
Like I said before, let's see some factual EVIDENCE, not unsupported rhetoric, opinions, speculations, WAG's, or misinformation.
I by no means want to be associated with a well known troll, however, I think the phrase is "Mettalic", not metal. Carbon is a non-metal, Tungston is a metal, and the resulting alloy is metallic, not a metal.
Apologies in advance if someone else pointed this out.
BottleBob's not actually that bad.
But Tungsten Carbide is not an alloy.
And geeze .... "OK what is the diferance between carbide and powdered metal ?" That's about like asking a neocon or a fundie what truth is.
Cliff: Depends on who you ask.
From Encarta Encyclopedia: ======================================================== Alloy:
Substance composed of two or more metals. Alloys, like pure metals, possess metallic luster and conduct heat and electricity well, although not generally as well as do the pure metals of which they are formed. Compounds that contain both a metal or metals and certain nonmetals, particularly those containing carbon, are also called alloys. The most important of these is steel. An alloy may consist of an intermetallic compound, a solid solution, an intimate mixture of minute crystals of the constituent metallic elements, or any combination of solutions or mixtures of the foregoing.
Historically, most alloys have been prepared by mixing the molten materials. More recently, powder metallurgy has become important in the preparation of alloys with special characteristics. In this process, the alloys are prepared by mixing dry powders of the materials, squeezing them together under high pressure, and then heating them to temperatures just below their melting points. The result is a solid, homogeneous alloy. Among the alloys made possible by powder metallurgy are the cermets. These alloys of metal and carbon (carbides), boron (borides), oxygen (oxides), silicon (silicides), and nitrogen (nitrides) combine the advantages of the high-temperature strength, stability, and oxidation resistance of the ceramic compound with the ductility and shock resistance of the metal.
"Alloy," Microsoft® Encarta® Encyclopedia 2000. © 1993-1999 Microsoft Corporation. All rights reserved. ========================================================
From Physics Daily: ========================================================
Tungsten carbide, WC or W2C, is an alloy of tungsten and carbon similar to titanium carbide. Its extreme hardness makes it useful in the manufacture of cutting tools, abrasives and bearings, as a cheaper alternative to diamond.
An alloy is a combination, either in solution or compound, of two or more elements, at least one of which is a metal, and where the resultant material has metallic properties. ========================================================
So Carbon is a metal per your lint?
Of course not. And you know very well that the excerpt from Encarta said no such thing. You've again creatively edited out the context to make it "appear" that something was said which really wasn't. You even intentionally removed the complete original excerpt to make a comparison with the full context more difficult. Here is the complete original alloy excerpt I posted:
=========================================================== From Encarta Encyclopedia.
Substance composed of two or more metals. Alloys, like pure metals, possess metallic luster and conduct heat and electricity well, although not generally as well as do the pure metals of which they are formed. Compounds that contain both a metal or metals and certain nonmetals, particularly those containing carbon, are also called alloys. The most important of these is steel. An alloy may consist of an intermetallic compound, a solid solution, an intimate mixture of minute crystals of the constituent metallic elements, or any combination of solutions or mixtures of the foregoing. =============================================================
Please note where it says: "Compounds that contain both a metal or metals and certain nonmetals, particularly those containing carbon, are also called alloys." Which contradicts the implication you were trying to make (that the article was stating that carbon was a metal), by you posting a sentence out of context.
Do you really think such misleading tactics are considered an honest search for the truth? If someone can't be trusted to tell the truth in a matter so inconsequential as a definition of alloy, then how can they be trusted to tell the truth in matters much more serious and important? This is just a little feeback 'ol buddy, but IMO, you should rethink your habit of engaging in this sort of self-serving maneuvering/misrepresentation, since it's not exactly improving your credibility.
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