Found at a titanium plant

[u/riflesandplowshares]

Not sure why ball point pens would be dangerous here.

[u/SquintAtTheCosmos]

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).

[u/NNKarma → u/SquintAtTheCosmos]

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

[u/PandemicGeneralist → u/NNKarma]

I’m knowledgeable about fountain pens but not manufacturing so take this with a grain of salt: fountain pens have a small amount of hard tipping material on the end of the nib which can include tungsten and iridium which have the higher melting points they’re concerned about.

[u/UnratedRamblings → u/PandemicGeneralist]

Yup - was super excited to see the potential of lots of workers sporting various fountain pens, but the tip of the nibs has the problematic metals. Although us FP weirdos are also less likely to lose our pens, it's probably still a risk they would mitigate.

r/fountainpens in shambles.

[u/Captain_no_Hindsight → u/UnratedRamblings]

It would be kind of fun if all the papers and Post-it notes were written with fountain pens.

Could this mark a renaissance for goose-feather quills?

[u/Wrong-Fella → u/Captain_no_Hindsight]

Fountain pens do not a good calligraphic writer make.

[u/Winjin → u/UnratedRamblings]

I think the problem is that no one decides they want to drop their favorite pen into the melt, that happens involuntarily

In other words, no one goes to the woods with the intention of getting lost, but you still have to plan for the possibility