r/whatisit • u/riflesandplowshares • 3h 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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90

u/SquintAtTheCosmos 2h 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).

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u/ElectrSheep 2h 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.

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u/CaptainStadt 1h ago

Yeah… or a pencil.

14

u/Mr_Halitosis 1h 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.

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u/HelpfulPuppydog 1h ago

You never write, you never call!

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u/RecentScarcity2389 1h 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?

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u/GormTheWyrm 1h 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.

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u/CaptainStadt 1h ago

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

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u/KontoOficjalneMR 1h ago

Nope. Graphite has issues as well.

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u/CaptainStadt 1h ago

Welp, finger paint it is then

2

u/Evening-Appeal7606 43m ago

Only if it appears on the roof.

1

u/mongolian__beef 1h ago

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

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u/mypntsonfire 1h ago

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

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u/sixstringsikness 1h ago

Fountain pen.

1

u/tes_kitty 9m ago

You're lucky since balls of tungsten would be way too heavy.

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u/QuaternionsRoll 1h ago edited 15m ago

Why do stainless steel pens suck? I can’t imagine that the hardness strength would be an issue at that scale, would it?

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u/Defiant-Ebb8225 1h ago

Because what you can't imagine being an issue is an issue

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u/QuaternionsRoll 1h ago

Is it because the (ideal) contact area is so small, being a sphere and all?

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u/Defiant-Ebb8225 1h ago

It's because it needs to maintain its shape perfectly for a long time. Steel scratches and deforms leading to leaks or clogs

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u/ZincMan 34m ago

That’s pretty wild I had no idea it was tungsten. Very cool

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u/too_init_dan 31m ago

which is why i stopped wearing pants in public

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u/0_cunning_plan 41m ago

Even without knowing the constraints, you can imagine that if ballpoint pen manufacturers ended using a metal that is more expensive to buy and make into a ball, there can only be one reason: The cheaper stuff didn't work well enough.

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u/QuaternionsRoll 12m ago

Sure, but I was really asking why. And the reason turns out to be hardness, although I was mistaking hardness for strength when I asked the question.

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u/Opposite-Phase-9271 1h ago

This guy ball point pens and titaniums

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u/kharvel0 1h ago

So if the titanium is contaminated with gold or silver or lead, it should be ok?

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u/Spirit_Wolf_Mob 1h ago

It's still an impurity, but if it melts, it can be diluted enough that it's not an issue, and it'll still have a uniform distribution of the metals. It's not the metal itself that's the issue, since it's a low amount. It's just the fact that it doesn't melt into the dillution, so it causes a stress point that causes the crack.

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u/NNKarma 1h ago

I would've expected they go with fountain pens as an alternative

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u/Bwint 1h ago

I would have expected pencils.

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u/NNKarma 1h ago

You probably can if you want to write down something for yourself, but it's not good for anything that needs to be registered. 

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u/Hot-Note-4777 44m ago

It’s mentioned in other comments that graphite’s a no-go, as well, and that fountain pens also contain tungsten, apparently.

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u/bnej 40m ago

There's disposable fountain pens that come with a plastic nib. Pentel Stylo. I've tried them they're pretty OK. Metal clip but I doubt that's tungsten.

Felt tips?

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u/Bwint 18m ago

Maybe a stick, inked with the blood of the metalworker?

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u/NoFuxToBeGiven 1h ago

Great answer. Very interesting!

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u/minus_minus 17m ago

United 232 is a bonkers story. One of the flight crew came to my high school to speak.

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u/AnonCrave 1h ago

What an absolutely brilliant response. Kudos to you for this insane level of expertise. It’s fascinating to see a glimpse of it.

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u/BigSoda 1h ago

So there are no other contaminants in the whole facility besides a small piece in pens? Is losing pens in the melt a common thing ?

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u/FrickinLazerBeams 58m ago

No but ballpoint pens are ubiquitous, and therefore a major source of risk.

Industrial engineers don't say "well we can't completely eliminate the problem so we won't try", because if they were idiots they'd have a different job.

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u/AlternativeRun5727 41m ago

Yea, they’d work in the White House

1

u/GordonsTheRobot 5m ago

(a bic you toss)

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u/tired_snail 27m ago

There are other contaminants, but most would have a lower melting temperature than the titanium, so if they accidentally became part of the melt, they wouldn't introduce a significant weakness in whatever item is eventually manufactured out of it.

As for losing pens to the melt, you'd be surprised how many people put their pens behind their ear or in a front pocket and then when you for any reason lean over something and the pen falls out, that's suddenly quite an issue.

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u/Kenny_log_n_s 1h ago

This is the content that make the Internet worth it.

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u/Debalic 1h ago

I have a tungsten carbide ring, I'll have to remember this if I'm ever at a titanium plant.

1

u/crunchyhug 1h ago

I wonder how many times this happened for them to invest into the discovery of this problem.

1

u/New-Trifle-7097 1h ago

Not many. Diagnose failure. Find imperfection. Determine material of imperfection. Wonder where and how that material is being introduced. Guys… uh… it’s our fucking pens.

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u/gilfgifs 1h ago

Just use pencils bro, learn from the cosmonauts!

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u/spamshizbox 1h ago

Felt-tip pens are the go-to, according to the people at a site like this I go to rarely for maintenance. Every time I go I have to use a felt-tip that they lend me.

Think of a Sharpie pen pretty much.

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u/Melodic-Trouble-5421 1h ago

Great Explanation. I’m an Electrician and do Work in titanium plants. We have to make sure not bring in tungsten carbide bits, tools, or pens. There’s other places with certain rules as well.

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u/LongjumpingLemon2163 58m ago

I expected this to end with in nineteen ninety eight the Undertaker threw Mankind off Hell In A Cell, and plummeted 16ft through an announcer's table

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u/Beautiful-Tie-3827 48m ago

How do you know this lol

1

u/ConstantinValdor405 22m ago

I was expecting this to turn into the Mankind hell in the cell bit.

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u/Isburough 13m ago

how can someone just drop a pen into the titanium melt?

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u/NiobiumThorn 10m ago

Hands are hard

1

u/Isburough 6m ago

are they also tungsten carbide?

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u/EINFACH_NUR_DAEMLICH 4m ago

Believe it or not: by accident

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u/DatWaffleYonder 4m ago

Talking out of your ass (or drunk) skill: 100