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The story of titanium

construction-physics.com

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Re: The story of titanium

#151

Post by ClumsyPilot »

saberience wrote: post #22
AlotOfReading wrote: post #20

Earlier quoted context omitted.

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.

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…

> We're not talking about exotic and expensive...

> "general" or common steel and "common"/"general" titanium

Why would you compare 'trash-quality' steel vs exotic and expensive material like Titanium?

That does not make any sence.

Re: The story of titanium

#152

Post by ClumsyPilot »

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…

> Then we could start replacing steel with titanium in many applications.

The world's production of stainless steel is growing almost exponentially and we are replacing many applications or ordinary steel with stainless. Every year millions of tons of steel are lost to rust.

Its a gigsntic shift noone is noticing

Re: The story of titanium

#153

Post by zardo »

SV_BubbleTime wrote: post #126

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, bu…

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

It is about children with hammers.

Re: The story of titanium

#154

Post by scythe »

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.

Wikipedia:

>4340 steel is an ultra-high strength steel

https://en.wikipedia.org/wiki/4340_steel

The alloy composition calls for 0.2-0.3% molybdenum and expects accuracy to within a few per mille for ten elements. Moly is considered so important that there are entire towns in the United States established to mine it to secure the military supply chain.

Re: The story of titanium

#155

Post by scythe »

MeImCounting wrote: post #70
metal_am wrote: post #54

Earlier quoted context omitted.

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.

IIRC you can buy titanium foil that you can just make stuff out of at home.

Re: The story of titanium

#156

Post by dredmorbius »

TylerE wrote: post #135
petertodd wrote: post #15

Earlier quoted context omitted.

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.

The Soviet Mikoyan-Gurevich MiG-25 was manufactured principally from stainless steel.

The result was a stunningly fast fighter aircraft, capable of Mach 3.2, though in practice engine overheating restricted operation maximum to Mach 2.83 (3,000 km/h), and even that for only 5 minutes at a time as the airframe and fuel would overheat. The MiG-25's mass necessitated huge wings (and overall dimensions), and limited maneuverability. Steel however provided better thermal-tolerance capabilities than aluminium, and lower cost and easier fabrication than titanium.

First flight 1964, introduced to active service in 1970.

That said, the aircraft is notable as an exception to your generally-applicable rule.

https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-25>

I suspect carbon fibre would also have thermal limitations for high-speed aircraft.

Re: The story of titanium

#157

Post by stevenwoo »

shiroiuma wrote: post #121
stevenwoo wrote: post #115

Earlier quoted context omitted.

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?

I do not, I just have owned a lot of titanium frames and parts over the years and just read obsessively about the subject. :)

Re: The story of titanium

#158

Post by postmodest »

dreamcompiler wrote: post #129
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.

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.

Plus: doesn't magnesium oxidize more readily than other metals? I would worry that grandpa's magnesium ladder is a death trap.

Re: The story of titanium

#159

Post by SV_BubbleTime »

Skunkleton wrote: post #133
SV_BubbleTime wrote: post #124

Earlier quoted context omitted.

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

And that makes perfect sense.

Thick walls on the iPhone are what are going to prevent X Y area which I suspect they need more than thickness.

Re: The story of titanium

#160

Post by AlotOfReading »

postmodest wrote: post #158
dreamcompiler wrote: post #129

Earlier quoted context omitted.

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.

Plus: doesn't magnesium oxidize more readily than other metals? I would worry that grandpa's magnesium ladder is a death trap.

Bulk metals are extremely difficult to ignite and magnesium in particular forms a very strong passivation layer on the surface as soon as it touches the air. Unless you're doing wildly inappropriate things like welding on it (tip: don't do this with any ladders, regardless of material), it's fine.
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