Live data from Hacker News

The story of titanium

construction-physics.com

61–70 of 188 posts

Re: The story of titanium

#61
post #57
post #56

Earlier quoted context omitted.

That company sells titanium pots, too. And they say “ Titanium leaves no metallic smell or taste.” I don’t believe it. Titanium is, mechanically, a great material for a lightweight pot, but in my limited testing, I don’t think it’s inert enough. Green tea in a titanium pot is especially nasty.

I had similar experiences with titanium cookware. Could it be acting as a catalyst to something that would otherwise not happen?

I don’t know.

My current favorite cooking surface is the coating used on Hestan Nanobond. It’s sold as “titanium” but, from reading the patent, I think it’s a bunch of layers of CrN, TiN, and AlN, applied by PVD in a process optimized to produce an attractive gray color that looks a bit like metallic titanium. It seems very hard, very durable, and does not obviously react with any kind of food. (And even if it did, unless something oxidized the Cr to +6 and made it soluble, nothing that might leach out seems likely to be harmful.)

The patent seems to expire fairly soon, and maybe the process will take off. I wonder if this coating could be applied to a lightweight titanium pot with good results.

Re: The story of titanium

#62

Huge fan of Titanium. If only we could find a cheap way to get the metal out of titanium dioxide. Like a Haber process-level breakthrough. Then we could start replacing steel with titanium in many applications. Think entire freight trains, cargo ships, containers, cars, trucks, tractors -- all that heavy steel replaced by titanium alloys. Enormous quantities of fuel and energy saved by lower density and higher streng…

Fatigue is why we use steel for everything, no other alloys have the practical strength and infinite life.

Like steel, titanium alloys have a distinct non-zero fatigue limit, and thus can be engineered to have infinite fatigue lives. Though the exact details differ and steel or titanium can be better depending on exactly what the conditions are.

Re: The story of titanium

#63
Almost everything about the article is wrong, oversimplified, or misleading.

Take this paragraph, for instance:

> But despite its abundance, it's only recently that civilization has been able to use titanium as a metal (titanium dioxide has been in use somewhat longer as a paint pigment). Because titanium so readily bonds with oxygen and other elements, it doesn’t occur at all in metallic form in nature. One engineer described titanium as a “streetwalker," because it will pick up anything and everything. While copper has been used by civilization since 7000 BC, and iron since around 3000 BC, titanium wasn’t discovered until the late 1700s, and wasn’t produced in metallic form until the late 19th century.

As this is basically a bunch of bullet points in paragraph form, it'll be easier to handle if we break it down:

> But despite its abundance, it's only recently that civilization has been able to use titanium as a metal (titanium dioxide has been in use somewhat longer as a paint pigment).

The same also applies to aluminum, magnesium, nickel, etc.

> Because titanium so readily bonds with oxygen and other elements, it doesn’t occur at all in metallic form in nature.

The same also applies to aluminum, magnesium, and even iron. (I mean, there's some meteoric iron, but it's very rare.) Pure metals are very rare in nature. What distinguishes iron and copper from aluminum and titanium is the energy required to split the oxide into metal.

> One engineer described titanium as a “streetwalker," because it will pick up anything and everything.

Titanium is not more reactive than aluminum and it's far less reactive than magnesium. In fact, it's slightly less reactive than iron overall. (i.e., more chemically stable under normal conditions and in contact with common acids.)

> While copper has been used by civilization since 7000 BC, and iron since around 3000 BC, titanium wasn’t discovered until the late 1700s, and wasn’t produced in metallic form until the late 19th century.

This has everything to do with the temperature required to separate the metal from the oxygen atoms binding it, and nothing to do with anything else. What's more, it applies even more strongly to aluminum, which was discovered in 1825 -- three decades after the discovery of titanium. (1791.) So there's absolutely nothing unique about titanium in this regard.

I could go on. But basically this is an "I hecking love science" article that barely scratches the surface of the subject -- and still manages to be subtly misleading.

Re: The story of titanium

#64

Huge fan of Titanium. If only we could find a cheap way to get the metal out of titanium dioxide. Like a Haber process-level breakthrough. Then we could start replacing steel with titanium in many applications. Think entire freight trains, cargo ships, containers, cars, trucks, tractors -- all that heavy steel replaced by titanium alloys. Enormous quantities of fuel and energy saved by lower density and higher streng…

Fatigue is why we use steel for everything, no other alloys have the practical strength and infinite life.

You are correct in that steel is harder and stiffer than titanium. Steel is also more re-usable, smelt-able than titanium.

However, when it comes to fatigue (which I assume, you are referring to fracture strain) titanium has a significant edge. The fracture strain for steel is roughly 15%, but for titanium alloys, it often reaches and exceeds 50%.

I don't say this to contradict you, but to point out that as with most things in life, "it depends".

Source: https://www.ulbrich.com/blog/titanium-versus-steel-a-battle-....

Re: The story of titanium

#67
post #55
post #48

Earlier quoted context omitted.

It’s not that great for blades as it doesn’t retain its edge as well as steel and is harder to sharpen.

It’s usually the frame and sides / scales that are made of titanium, never the blade afaik. Except maybe in some multitool keyring single piece doohickeys, but it’s not expected to cut anything beside the tape on your packaging.

Titanium so widely desirable for knife scales because of not only its strength to weight benefits but also interesting finishes that can be applied for instance anodization can give incredibly beautiful iridescent colors in a wide spectrum of potential colors and tones. I dont know how interested you are in modding your pocket knife but there are several very talented people that can do just stunning colorful and textural finishes on titanium.

Re: The story of titanium

#68
post #56
post #10

Earlier quoted context omitted.

https://nearzero.co/products/shovel They exist! Meant for backpacking/back country work. I spent a summer as a wilderness search and rescue intern/volunteer/grunt/mule during college and was shocked at how much weight could have been saved with better gear. There’s just a minimal market for it.

That company sells titanium pots, too. And they say “ Titanium leaves no metallic smell or taste.” I don’t believe it. Titanium is, mechanically, a great material for a lightweight pot, but in my limited testing, I don’t think it’s inert enough. Green tea in a titanium pot is especially nasty.

In the backpacking and bicycle-travel community, titanium pots are widely regarded as good only for boiling water in, since they don't distribute heat as well as aluminium for more complex cooking.

Re: The story of titanium

#69
post #56
post #10

Earlier quoted context omitted.

https://nearzero.co/products/shovel They exist! Meant for backpacking/back country work. I spent a summer as a wilderness search and rescue intern/volunteer/grunt/mule during college and was shocked at how much weight could have been saved with better gear. There’s just a minimal market for it.

That company sells titanium pots, too. And they say “ Titanium leaves no metallic smell or taste.” I don’t believe it. Titanium is, mechanically, a great material for a lightweight pot, but in my limited testing, I don’t think it’s inert enough. Green tea in a titanium pot is especially nasty.

This is actually a plot point in H. Beam Piper's _Little Fuzzy_:

https://www.gutenberg.org/ebooks/18137

the audiobook read by Tabithat is just about professional quality and is highly recommended:

https://librivox.org/little-fuzzy-by-h-beam-piper/

Re: The story of titanium

#70

Earlier quoted context omitted.

Pure elemental titanium has much less desirable material properties than various titanium alloys which are what you encounter most commonly. It is very uncommon to encounter elemental titanium outside of a chemistry lab.

Grade 1 is still pretty common for ultralight backpacking items like pots and pans due to its ductility.

Thats cool! I didnt know there were specific common applications where grade 1 would be desirable compared to the stronger alloys available.
Post reply on HN