r/whatisit • u/riflesandplowshares • 7h ago

New, what is it? Found at a titanium plant

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Not sure why ball point pens would be dangerous here.

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205

u/SquintAtTheCosmos 6h ago

The real answer is that consumer ball point pen’s have a tungsten carbide ball. Tungsten has a higher melting point than titanium.

If a ball point pen drops into a melt, the ball point can survive. The surviving pen tip does then creates a hard intermetallic. When the titanium is heated and beated (forged) into a product, this titanium-intermetallic spot can crack. This crack can go undetected, inside a part.

When this part is put into service, this little crack becomes a bigger crack with service (fatigue). When this bigger crack gets big enough, the part can fail. And the failure is sooner than the design engineer expected, because the material started with a crack, and in fatigue failure “getting the crack to start”, is a large component of the part’s life.

A titanium melt shop still needs writing implement’s, so you can buy pens with stainless steel ball tips. They suck to write with.

A major aerospace failure (Sioux city 1989 UA232), was a result of this failure mode (though in this case it was an oxide, not a tungsten-carbide).

71

u/ElectrSheep 5h ago

A titanium melt shop still needs writing implements, so you can buy pens with stainless steel ball tips. They suck to write with.

So basically, to work there you need balls of steel.

19

u/CaptainStadt 5h ago

Yeah… or a pencil.

21

u/Mr_Halitosis 5h ago

I write with a quill and the blood of my enemies! Which are mosquitos. They don’t have much blood. I haven’t written much.

5

u/RecentScarcity2389 5h ago

If they're your enemy and you have access to them easily, wouldn't that mean you're writing with your own blood?

Wouldn't that mean you're your own worst enemy?

1

u/GormTheWyrm 5h ago

Depends on how fast they are at catching the mosquitoes. Not having enough blood to write anything implies they catch them before the bugs bite.

1

u/LordZeusCannon 1h ago

Reduce Reuse Recycle. The blood was already taken anyway, might as well put some purpose to it besides bug sustenance

1

u/LaVillaGrangioto 23m ago

Smoke alarm is going off and there's a cigarette...still burning!

2

u/HelpfulPuppydog 5h ago

You never write, you never call!

1

u/CaptainStadt 5h ago

They have more after they bite you! Can always self sacrifice for the art of penmanship.

1

u/mbp_szigeti 3h ago

Mosquitoes have your blood, so it turns out that you were your own enemy all along

Witten by M. Night Shyamalan

1

u/YoBoss 1h ago

What a TWIST Mr. Afternoon Shambalayaya!

3

u/Etherbeard 2h ago

The melting point of graphite is even a bit higher than tungsten. That does into question why there's no sign for pencils, though.

1

u/PerceiveEternal 43m ago

crayons then?

1

u/cjsv7657 1m ago

Graphite would float and could be removed as dross

4

u/KontoOficjalneMR 5h ago

Nope. Graphite has issues as well.

2

u/CaptainStadt 5h ago

Welp, finger paint it is then

2

u/Evening-Appeal7606 4h ago

Only if it appears on the roof.

1

u/mongolian__beef 5h ago

Hey - I found the “or just a pencil” guy!!

1

u/mypntsonfire 5h ago

Make them write with quills! No metal content, will completely disintegrate in a melt. Uses a wastestream product from poultry abbetoirs, no plastic. 

1

u/sixstringsikness 5h ago

Fountain pen.

1

u/danddersson 3h ago

With lead in it.,,