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The story of titanium

construction-physics.com

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Re: The story of titanium

#121

Post by shiroiuma »

stevenwoo wrote: post #115
kylehotchkiss wrote: post #108

Earlier quoted context omitted.

This is super cool, I didn't realize the reason would be so complex. Thanks for explaining!

It's been done but the cost is very high compared to other materials because of the amount of specialized labor and only boutique builders offer one, the legs are really fat so it has poor aerodynamics so it's only suitable for off-road as a drop in replacement for a bicycle frame built for a suspension fork to account for the crown to tire distance and almost everyone has switched to suspension off-road. I've ridden…

You seem like you'd know the answer to this question: why do so many aluminum bicycles have carbon-fiber forks?

Re: The story of titanium

#122

Post by garbanzoPDX »

> it formed the literal backbone of the most advanced aerospace technology on the planet.

I'm going to be pedantic here, but I feel like it needs to be said: no, it was not the "literal" backbone aerospace technology. It was the "figurative" backbone. There, I said it.

Re: The story of titanium

#123

Post by lazide »

TexanFeller wrote: post #99
pasabagi wrote: post #82

Earlier quoted context omitted.

That's true. On the other hand, people have been working with flint for longer than there have been people, and it remains fiendishly hard to make anything with it.

The ground is covered with flint arrowheads in various parts of TX that I’ve visited and/or inhabited. It’s really hard for me to imagine Indians crafting so many of them if it were that hard to work with.

They had no other viable options. It is hard to work with.

Re: The story of titanium

#124

Post by SV_BubbleTime »

myself248 wrote: post #9
cyberax wrote: post #7

Earlier quoted context omitted.

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.

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 - most recently as an example by Apple. Aluminum was fine, but had thick walls. Steel allowed thinner was but was heavier. Titanium allowed for thin walls and more internal volume, but at a higher cost.

Basically, if you don’t have a size limit, aluminum is great! But most things have size limits, and titanium allows you to trade size for cost.

Re: The story of titanium

#125

Post by SV_BubbleTime »

scythe wrote: post #106
MeImCounting wrote: post #37

Earlier quoted context omitted.

No the parent is correct. Steel is by and large stronger than titanium of the same size. Pray tell what is this "most commonly used alloy of steel"? Because just fyi different steel alloys are used for different applications just like different titanium alloys are also used for different applications. Titanium has excellent strength to weight properties compared to steel. A 4mm titanium plate would absolutely be dent…

Steel has a range of strengths. The "most commonly used steel" is probably just mild steel and yeah Ti-6Al-4V is going to be the rough equal of mild steel on strength broadly assessed. But a high strength steel alloy will be three times that strong, and titanium can only be pushed so far.

I would use “cold roll” instead of “mild steel”.

But otherwise, yea irrc… Grade5 Ti (6AL4V) is approx equal to ultimate tensile of 303 stainless (extremely common) at 50% the weight.

BUT… Ti doesn’t even get close to 600 steels (like Inconel) or even common 17-4PH, etc.

Re: The story of titanium

#126

Post by SV_BubbleTime »

Heads up… except for mine almost none of the comments here mention Grade 5 (6AL4V).

This thread is a ton of people talking about things they think they understand but haven’t actually directly worked with. Just making things up or repeating things they heard once.

Anyone who actually uses it will know Grade 2, 5, 12, 23 etc.

I don’t mind particularly, there are some clearly educated people talking about chemistry, but it is important to note how many people here are talking out their asses.

The top current comment is about being unable to dent 4mm Ti plate with hammers - complete BS.

Re: The story of titanium

#127

Post by messe »

garbanzoPDX wrote: post #122

> it formed the literal backbone of the most advanced aerospace technology on the planet. I'm going to be pedantic here, but I feel like it needs to be said: no, it was not the "literal" backbone aerospace technology. It was the "figurative" backbone. There, I said it.

It does not need to be said.

The use of literally as an intensifier goes back centuries, and is well-accepted. Move on.

Why choose this hill to die on when there are far more interesting things to discuss?

Re: The story of titanium

#128

Post by dreamcompiler »

garbanzoPDX wrote: post #122

> it formed the literal backbone of the most advanced aerospace technology on the planet. I'm going to be pedantic here, but I feel like it needs to be said: no, it was not the "literal" backbone aerospace technology. It was the "figurative" backbone. There, I said it.

Since the A-12 was 93% titanium, it's virtually certain that its skeletal frame was made of the metal. The word "literal" applies.

Re: The story of titanium

#129

Post by dreamcompiler »

myself248 wrote: post #9
cyberax wrote: post #7

Earlier quoted context omitted.

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.

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.

Magnesium stepladders are great until one catches on fire because you try to weld something onto it or get it too close to a welding torch. Then things get spicy.

Re: The story of titanium

#130

Post by petertodd »

johnwalkr wrote: post #101
petertodd wrote: post #50

Earlier quoted context omitted.

Also fatigue resistance. Bicycle design is a good example of where this matters: steel has a significant fatigue limit, and can endure cyclic stresses below that limit indefinitely. Aluminum has no fatigue limit, so any flexing is inevitably eating away at fatigue life. Thus aluminum bike frames have to be made much stronger and stiffer than otherwise necessary, to avoid bikes breaking unexpectedly due to fatigue. An…

For a rigid road bike aluminum can definitely be made stronger and lighter, even though what you wrote about fatigue limit is technically true. People like steel because they feel it’s more comfortable to ride. For mountain bikes, you will find almost zero steel bikes. Here the stiffness and lightness of aluminum (and carbon fiber at the high end) is almost universally preferred. One advantage that adds to the potent…

> For a rigid road bike aluminum can definitely be made stronger and lighter,

Absolutely. What I meant was that while an aluminum bike frame can be lighter than steel, it's not as much lighter than steel than you'd expect. Steel bike frames tend to be only ~15% heavier than aluminum, not 50%.

Personally I bought a steel road because the difference in weight vs the aluminum alternative was small enough that I decided to go with the bike that looked nicer, and would last longer. Besides, I could use to lose a lot more weight than any bike ever could...

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