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.
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).
Rust is a specific form of oxide, ferric (III) oxide, so it can only form
where there's iron.
Same thing? I doubt it, due to brittleness and differences in expansion
rate. But I wouldn't know.
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.
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
Nope
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.
:> 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...
Hmm. I would say that tungsten =/ tungsten carbide...
Jim
================================================= please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
=================================================
Many tungsten carbide formulations contain cobalt power, which is magnetic.
Some tungsten carbide formulations (not, generally, ones used for cutting
tools) contain iron powder.
Only if it contains iron powder.
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.
I don't get the distinction.
Carbide runs around 10 points higher on the Rockwell C hardness scale than
the hardest steel.
No.
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
On 6 Feb 2004 08:45:58 -0800, snipped-for-privacy@hotmail.com
(benwoodward.com) wrote:
Ever stick a canadian nickel to a magnet?
Others have mentioned cobalt, but nickel is a more common metal which
is attracted to a magnet.
American nickels aren't attracted to a magnet because it isn't a pure
enough form of nickel. Canadian nickels/quarters are.
Dave
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
=================================================
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 snipped-for-privacy@pacbell.net
On 6 Feb 2004 08:45:58 -0800, snipped-for-privacy@hotmail.com
(benwoodward.com) wrote:
Silmanal is a permanent magnet. Composition?
86.8 silver-8.8% manganese- 4.4% aluminum
None of the elements usually classified as ferromagnetic are present
in that alloy.
Aluminum is attracted to a magnet and certainly is not ferrous. It is
classified as paramagnetic but paramagnetic materials are in fact
magnetic. Off hand I can't think of any material that isn't
ferromagnetic, paramagnetic, or diamagnetic.
On 5 Feb 2004 10:38:56 -0800, snipped-for-privacy@hotmail.com
(benwoodward.com) wrote:
Tungsten is the element W.
Carbon is the element C.
Tungsten Carbide has the molecular formula WC.
Pure tungsten carbide contains no iron, and thus is non-ferrous.
Tungsten carbide items may be made from powdered tungsten carbide,
subjected to heat and pressure to bind it together. Other powder
metals are probably added to the WC to help it stick together.
Even if some iron powder was added, it probably isn't considered
"ferrous".
So overall, I believe the answer would be 'no'.
Dave
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
=================================================
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.:-)
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
=================================================
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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