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The story of titanium

construction-physics.com

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Re: The story of titanium

#131

Post by dreamcompiler »

cwillu wrote: post #119
saberience wrote: post #22

Earlier quoted context omitted.

We're not talking about exotic and expensive varieties of steel though. We're just talking about "general" or common steel and comparing it to unalloyed "common"/"general" titanium. Remember, Steel is itself an alloy, Titanium is an element. If you start comparing Titanium alloys to Steel then the comparison gets even harder. Titanium alloys are in general stronger than steel as well as much lighter and more corrosio…

So called “mild steel” would be far more accurately called “iron”, the carbon content is insignificant.

The carbon content of mild steel is low but not insignificant. Pure wrought iron [0] is a dream to forge and it has a huge grain structure. It's more ductile than mild steel but it's also not as hardenable or tough as mild steel [1]. That little bit of carbon in mild steel makes a big difference.

[0] I mean real wrought iron -- the almost 100% elemental stuff -- like the Eiffel tower is made of. This is practically unobtainable today. The "wrought iron" you commonly see for sale nowadays is always mild steel. And "cast iron" is actually very high carbon steel, not iron. Cast iron so high in carbon that it's brittle and cannot be forged or easily welded.

[1] It's a myth that mild steel cannot be hardened. With a proper wetting agent added to the quench, you can harden it significantly.

Re: The story of titanium

#132

Post by saiya-jin »

cyberax wrote: post #7
danielodievich wrote: post #3

As a kid in my father's workshop we had several 4mm thick titanium plates, scavenged from some industrial stuff in USSR research facility nearby. I had a lot of fun getting my visiting friends tey to dent it with hammers. No matter how hard you struck it just didn't care. Only the oxidation patina would show some trace of impact. It was absolute magic to me. And so incredibly light!

When the USSR collapsed, a lot of defense companies pivoted to civilian production. A factory in my town was producing titanium shovel heads. They were awesome, unbelievably light, but very durable. They also made nice sparks when dragged across concrete pavement.

Mountaineering ice screws. Its a dream for pro alpinists, since you have to drag every gram up there in thin air, so focus on weight saving is extreme, ie drilling holes into aluminum spoons before 8000m expeditions was normal in 70s-80s in eastern Europe block. Normal stainless steel ones are much heavier.

Re: The story of titanium

#133

Post by Skunkleton »

SV_BubbleTime wrote: post #124
myself248 wrote: post #9

Earlier quoted context omitted.

Decades ago, Sears sold magnesium stepladders. I've used one, and it's freakishly light, a 6-foot step ladder that you can walk around with balanced on one finger. I've always wondered what a titanium one would be like.

Aluminum and magnesium are lighter than titanium at the same strength. The idea is you can use less titanium in the application you would use aluminum, but this has limits. If your ladder was .200” wall thickness, you might in theory get away with a .070” titanium for the same weight, but you start running into mechanical stresses or assembly issues or manufacturing. Titanium is useful when you need internal volume -…

The iPhone 15 pro is mostly aluminum. There is about a 1mm thick band of titanium around an aluminum frame.

https://www.apple.com/newsroom/2023/09/apple-unveils-iphone-... https://www.youtube.com/watch?v=S_W73ouKtjU&t=605s

Re: The story of titanium

#134

Post by tako »

PakG1 wrote: post #109
londons_explore wrote: post #28

Earlier quoted context omitted.

If you can 3D print titanium, then you can make a honeycomb structure overcoming this problem.

Coincidentally, you can. https://www.sciencedirect.com/science/article/abs/pii/S00260...

NI think AI assisted development needs comments to make better informed decisions about the code Needed to accomplish the task.

Re: The story of titanium

#135

Post by TylerE »

petertodd wrote: post #15
myself248 wrote: post #9

Earlier quoted context omitted.

Decades ago, Sears sold magnesium stepladders. I've used one, and it's freakishly light, a 6-foot step ladder that you can walk around with balanced on one finger. I've always wondered what a titanium one would be like.

A lot heavier actually. In an application like a stepladder, you have to work with certain minimum dimensions for the stepladder to be practical (eg rungs and sides have to fit in the hands nicely). You also have to have certain minimum thicknesses on the parts to have sufficient resistance to local deformation (eg dropping a hammer on the rungs). That forces the parts to be significantly larger and stronger than the…

This is also why aircraft use aluminum, despite the major downsides (finite fatigue life, mainly). There’s just no way steel would work (far too heavy). Titanium is awesome but a royal pain to work with. Carbon fiber is starting to come in but it has issues to - although they’ll be overcome with time.

Re: The story of titanium

#136

Post by rowanG077 »

AlotOfReading wrote: post #20
saberience wrote: post #16

Earlier quoted context omitted.

I mean, I'm no materials scientist but one google tells me that Titanium is AS strong as steel but much less dense. I just browsed through the top 10 Google results and everyone states that titanium is roughly equal to steel in strength but with various other benefits. So your comment is definitely off-base somewhere, you make it seem like steel is much stronger, which clearly isn't the case.

Steel's strength varies by orders of magnitude depending on the alloy and heat treatment. It's an incredibly flexible family of materials. Some members of that family are far stronger than anything in the titanium family, e.g. 4340 steel has a nominal yield strength of >1800 MPa, compared to <1300 MPa for Ti 10-2-3.

There are definitely steels that lose out to grade 5 Titanium. There are also steels that beat all Titanium grades. It's not so simple to say steel is stronger then Titanium. Some steels are stronger then titanium. Some Titanium grades are stronger then Some steels.

Re: The story of titanium

#138

Post by thaumasiotes »

kylehotchkiss wrote: post #30
scrlk wrote: post #11

I can't help but recall Steve Jobs introducing the PowerBook G4 Titanium: > "Titanium! It's made out of titanium! Like the spy planes! This is an incredible material, it's stronger than steel yet lighter than aluminium." https://youtu.be/bNHkrnU77m0?t=92

I could see a day when titanium laptops return. Apple has invested in the some of the best mass machining in the world. I wonder what it’d look like sandblasted like their laptops and with their new coatings.

> I could see a day when titanium laptops return.

I don't get it. I was issued a metal macbook once. I had to buy a plastic case for it, because the bare metal scratched my fingernails.

Why would we want a hard metal case instead of a soft plastic one?

Re: The story of titanium

#139

Post by hdivider »

pasabagi wrote: post #75
hdivider wrote: post #51

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…

I think it could be one of those 'grass-is-greener' scenarios. Steel is really nice to work with. It's strong and elastic and you can do all sorts of things to alter its properties, like even in a home shop. Titanium always looks really hard to work with, just from the few times I've seen youtube types get some into their lathe chucks. Would the added (in some ways just different) performance make up the difference?…

That's why I said titanium alloys specifically. With such a large-scale industrial transformation, definitely many alloys would be explored, to fit the needs of new industries. We don't use pure iron for any serious applications either.

Re: The story of titanium

#140

Post by tim333 »

thaumasiotes wrote: post #138
kylehotchkiss wrote: post #30

Earlier quoted context omitted.

I could see a day when titanium laptops return. Apple has invested in the some of the best mass machining in the world. I wonder what it’d look like sandblasted like their laptops and with their new coatings.

> I could see a day when titanium laptops return. I don't get it. I was issued a metal macbook once. I had to buy a plastic case for it, because the bare metal scratched my fingernails. Why would we want a hard metal case instead of a soft plastic one?

Plastic cases flexing can damage the electronics inside hence most of the Apple stuff being metal.
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