Tungsten-cobalt alloys extremely carcinogenic?

They're made of tungsten CARBIDE and cobalt. And other stuff.

I've never heard anything about it. Keep in mind that tungsten is a lot more chemically active than tungsten carbide. But that's not an answer to your question.

Any effect is most likely due to the cobalt. As far as I know, and I do a lot of work in a plant that processes tungsten, tungsten is not a known carcinogen. When you speak of tungsten/cobalt end mill, I assume you mean tungsten carbide/cobalt.

Re the cobalt:

"Carcinogenicity- International Agency for Research on Cancer (IARC) has listed cobalt and cobalt compounds within group 2B (agents which are possibly carcinogenic to humans). ACGIH has placed cobalt and inorganic compounds in category A3 (Experimental animal carcinogen- the agent is carcinogenic in experimental animals at a relatively high dose, by route(s), histologic type(s), or by mechanism(s) that are not considered relevant to worker exposure.) Cobalt has been classified to be carcinogenic to experimental animals by the Federal Republic of Germany."

Which I take to mean, unless you're making body piercings out of old carbide tools, don't worry about it

I wouldn't say they are "our" battles, more like battles between a group of people who use this group as a political pissing ground, of which you can count me out.

Jon

On May 3, 12:58=A0pm, Ignoramus18758

Some of the high speed tool steel contains significant amounts of Tungsten. T1, the original high speed steel, is 18% Tungsten. T15 is one of the current super tool steels and it contains 12 % Tungsten. And of course your TIG electrodes are almost pure Tungsten. So I would consider washing your hands before eating. But I do have not read anything on how toxic tool steels are.

Dan

100% of rats implanted with a pellet of such

What would be the fate of the rats if they *implanted* a lead pellet? Or how about if they *implanted* a copper pellet?

To me the difference is a big one. Carbide tools have been in machine shops for a really long time so I think if the use of the tool was an issue then it would have been an issue in machinists. If you were a wounded soldier with a chunk of shrapnel made from DU or tungsten/ carbide that might be a real worry but if it is not reacting with your internal body fluids it is probably a non issue.

Don't they make tooth implants from tungsten?

Roger Shoaf

Well, it has been shown that if you run the smoke of 1000 cigarettes through a liquid nitrogen cold trap, collect the tar, dissolve it in acetone, and paint it onto the skin of a hairless lab mouse that has a genetic predisposition to cancer, that by golly, the mouse gets skin cancer!

Thanks, Rich

Life causes cancer. If you don't die of cancer it was simply because something else got your first.

I would prefer "something else", thank you very much.

i

Shot by a jealous husband, when you're 90.

Modern medicine has made it possible to die from diseases we never lived long enough to contract 100 years ago.

Wes

Alzheimer's?

OSHA on Cobalt:

"Apparently low toxicity" of Tungsten: jsw

That's naughty, but a good start.

i

I would take that over cancer, any day.

i

Tungsten carbide implants:

jsw

I can see how a sliver of tool steel could get embedded in my body, like a splinter, or I could inhale tingsten dust from tool or electrode grinding.

i

Tungsten:

>

The article talks about using tungsten carbide in place of silicon in sensors, so presumably there's no cobalt binding the WC crystals together, as in what's loosely referred to as "carbide" when speaking of cutting tools.

Which reminds me of some confusion that occurred around some little heat treat fixtures I designed. They were made entirely from tungsten and my customer supplied the material to the shop that was making them. But someone in the shop misinterpreted the material callout on a print for couple little pins and figured they could save some time by using ground tungsten carbide rod in place of the supplied oversize W rod. The cobalt melted when the fixtures went into the furnace.

I believe that cheap tungsten carbide jewelry on eBay is made of recycled end mills, with cobalt binding. The more expensive tungsten carbide jewelry is made with nickel binding.

i

Just for the record, there is quite a bit of tungsten used in production machining. It's called "heavy metal," rather than being identified as tungsten, and it's widely used for production boring bars and deep-hole insert-type drills.

Iscar, among others, offers it as an option for several of their insert-type toolholders for internal-machining tools. Some tool manufacturers offer it as an option to tungsten carbide or steel.

Its Young's modulus is similar to that of tungsten carbide, but I think it has better elongation, so it's not as brittle. It is expensive.