The story of titanium(construction-physics.com) |
The story of titanium(construction-physics.com) |
They were awesome, unbelievably light, but very durable. They also made nice sparks when dragged across concrete pavement.
I've always wondered what a titanium one would be like.
I remember reading elsewhere that the CIA set up a bunch of front operations across the world to buy titanium (or maybe titanium ore) from the USSR without them finding out what it was being used for. They didn't want the "Ship to:" part of the order form reading "Lockheed Skunkworks, Burbank Califoria". Heh.
Highly reccomended and goes into further engineering and design challenges of the RS-71 Blackbird and its titanium construction.
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 strength. In many applications, it would likely make stainless steel obsolete.
Trillions of dollars of value may be locked up in such a breakthrough.
On my finger is a tungsten carbide ring, it's extremely dense (that of gold, slightly heavier than uranium), and has a lot of interesting properties. It's warmed quickly by my fingers, and rings the most beautiful tone when I strike it with some bar stock of AI.
Wolfram has been a very nice metal in my life, I wish it was more common, and would love to try to add some knurling to it.
I also have a titanium pocketknife (James Brand), carabiner, keyrings, pens, camera (fujifilm makes a few), and some beloved snow peak dishes. And the silly titanium iPhone. It’s such a great metal to make things to carry with.
I've been searching forever for decent keyrings. There's a few carabiners (though the titanium ones are hard to find there too, and usually covered in obnoxious branding). But keyrings especially seem to be an under-served market. There's either (1) the usual mass-produced, flimsy, cheap garbage, or (2) something tougher and more expensive, but covered in branding.
I've settled with (2) for now (though it's not even titanium), but it'd be nice to not have to look at a giant billboard every time I pull out my keys.
Source - my wife breaks out from nickel in jean rivets but niobium is good enough for piercings
> "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."
There was a blog called "Atomic Delights" that would explain the manufacturing processes featured in the videos. Found it super interesting, especially considering the challenge of shipping products at Apple level volumes.
A MBP with the natural titanium finish as seen in the iPhone 15 Pro would be fantastic.
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?
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.
It weighs just 6.6 lbs. (the page says 6.5 but I had to have him add a bit cause I got too swole in the lats a couple of years ago.)
It's fun to have someone try it on then watch them struggle as they can't figure out how to get it off lol
If you bend over and stick your arms down it basically slide off on its own.
What's really interesting is the ringing sound it makes when you play with it or move around wearing it, it's a noticibly higher pitch than steel is.
I also have a necklace/spacepen lanyard, wallet chain, and coif made of titanium by Bim also. My keyrings and bottle opener are also titanium. It's such a cool metal. Kind of a pity it makes a very poor knife blade. Speaking of: I also replaced the screws and hinges of my bespoke Benchmade knife with titanium ones, because why not?
A bit obsessed as you can tell.
tl;dr I have a mithril shirt
Welded or rivited rings would be much more robust. Especially vs piercing weapons, like arrows or fighting knives.
But much more expensive.
https://history.stackexchange.com/questions/28152/when-and-h...
study ref: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3176400/
Tales About Metals
https://archive.org/details/VenetskyTalesAboutMetals
On Rare and Scattered Metals
https://archive.org/details/OnRareAndScatteredMetalsTalesAbo...
>"The earth contains a lot of titanium - it’s the ninth most abundant element in the earth’s crust. By mass, there’s more titanium in the earth’s crust than carbon by a factor of nearly 30, and more titanium than copper by a factor of nearly 100."
>"Titanium was nearly as strong as stainless steel, but weighed 40% less."
Consider Steel I-Beams, used in construction:
https://en.wikipedia.org/wiki/I-beam
Observation: If the workability difficulties of Titanium could be solved, at scale -- then not Steel, but Titanium I-Beams -- could be produced, en masse...
If this could be done cheaply enough, then, in the future, Titanium I-Beams -- produced in the U.S.A. -- could retake the worldwide market for construction I-Beams that was historically lost when other countries started producing Steel I-Beams cheaper than the U.S. did...
Anyway, an excellent article!
Now this is just showing off.[1] Daishin and Open Mind started with a 60 kilogram cylinder of titanium and milled a very detailed crown out of it. 300 hours of CNC machining time on a very good 5-axis mill. Most of the metal ends up as scrap.
The software for this is called HyperMill. If you have to ask how much it costs, you can't afford it.
https://nationalinterest.org/blog/buzz/crazy-story-how-russi...
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.
It is about children with hammers.
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.
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?
The article so far can be summarized as "people played around with titanium, but had no idea what to use it for" so why is the bureau suddenly trying to scale up production, or even mass producing it in the first place? It wasn't until 1948 that they identified engineering applications.
Also, this time seems to be going a bit differently... Perhaps timing is everything (see: bored people with their Thanksgiving families today...)
Time of day, time of week, other prominent distractions, etc have an increasingly outsized influence.
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? No idea. I mean, would people use so much aluminium if it wasn't straightforward to extrude it into interesting shapes? I don't think I would.
The straight characteristics of a material are one thing: what you can actually do with it are another.
Looks like alloys are much more mallable, while losing almost none of the qualities of pure titanium.
Also: Go nukkular, high-temperature to be specific.
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-....
Based on this tech: https://en.m.wikipedia.org/wiki/FFC_Cambridge_process
Still waiting for my titanium girders though...
In my mind, this is what real technology entrepreneurship looks like. As opposed to the latest crypto or social media thing.
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
the oxides of aluminum, magnesium, and nickel were not in use as paint pigments
> What distinguishes iron and copper from aluminum and titanium is the energy required to split the oxide into metal. (...) Titanium is not more reactive than aluminum
the particularly relevant issue here, as i understand it, is that titanium has a stable carbide, which prevents you from reducing it carbothermically; you end up with titanium carbide instead of titanium metal. aluminum's carbide is unstable even in water, while iron's carbide is mechanically strong but still easy to reduce to iron with air. copper's carbide is poorly characterized and even more unstable, and it even occurs native
there are other things that titanium reacts more strongly with than aluminum does. titanium tetrachloride, for example, which is mentioned in the article, isn't a mere salt like normal chlorides; it's a volatile fuming liquid, because titanium forms covalent bonds with the chlorine like a motherfucking nonmetal. you can argue about whether this makes it more or less reactive than aluminum in this context; the reaction produces more energy per metal atom but less energy per chlorine atom
this kind of dirty trick is why titanium wasn't isolated until decades after the creation of metallic calcium, sodium, potassium, aluminum, and even the isolation of some of the rare earths
so i think the characterization in the article is fair
Aluminum oxides were used as a pigment, predominantly in blue (cobalt aluminum oxide) but also in white.
In any case, the dominant white dyes of the Early Modern period -- and prior periods -- were lead based. The presence of TiO2-based pigments is actually one good way to identify a modern forgery.
> the particularly relevant issue here, as i understand it, is that titanium has a stable carbide
This turned out to be solvable via calciothermic or magnesiothermic reduction -- which is now effectively the go-to method for just about everything that can't be reduced with carbon. All titanium dioxide reduction processes demand quite a lot of energy, though; more than aluminum and far more than iron.
For instance, if you have pure Titanium, pure Magnesium, pure aluminum in a vacuum at room temperature and proceed to introduce oxygen, you get the following reactions (simplified elemental chemical reactions, the Enthalpy of formation is what is important here):
Ti + O2 -> TiO2 (Std. Enthalpy of formation is -945kJ/mol)
Mg + O -> MgO (Std. Enthalpy of formation is -601kJ/mol)
4Al + 3O2 -> 2 Al2O3 (Std. Enthalpy of formation is -1675kJ/mol)
As a result, aluminum is most reactive, followed by titanium, then magnesium.
This is the reason why aluminum is used in solid rocket motors and various other explosive devices.
Under different conditions, these numbers may change: for instance a reaction with water instead of air may yield different enthalpies. At quick glance in water, titanium is actually least reactive when compared to aluminum and magnesium.
https://en.wikipedia.org/wiki/Reactivity_series
So from a high enough vantage point, Ti is very slightly less reactive than Al, less reactive than Mg, and not too far from Fe. A far cry from being "a streetwalker" of a metal.
Maybe anodized titanium would work better? I don’t know what the chemistry behind the problem is, but even stainless steel kills green tea after a while.
Though it's heavier than an insulated plastic mug, and _way_ more expensive.
the magnesiothermic reduction is the actual reduction step of the kroll process, though
https://solar.lowtechmagazine.com/2009/06/how-much-energy-do...
My super-scientific "is titanium" test involved trying to get a fridge magnet to stick to them. it won't, and a normal keyring will. Yes, that risks it being aluminum. Other reviews state they put one against their sanding machine and got white sparks which was an additional positive sign.
If you want to confidently get titanium, these: https://thejamesbrand.com/products/titanium-keyring
They also make the carabiner I mentioned: https://thejamesbrand.com/products/the-mehlville?variant=312...
And here's a beer bottle opener to complete your collection: https://thejamesbrand.com/products/the-tjb-bottle-opener-tit...
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.
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.
https://www.gutenberg.org/ebooks/18137
the audiobook read by Tabithat is just about professional quality and is highly recommended:
Garage Grown Gear has some of the trendy light and ultralight stuff.
Except maybe in some multitool keyring single piece doohickeys, but it’s not expected to cut anything beside the tape on your packaging.
you can grind it into whatever shape you want if you're careful about silicosis
Nice multi-purpose titanium laptop. You can even trim your fingernails on the same!
Most people are not looking to scuff up the face of their fingernails, which is what happens when you handle such a laptop naturally.
If plastic cases bore any significant risk of damaging the electronics, someone would probably have noticed that by now.
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.
[0] Concretely, this means that, when cooking solid food, the parts of the pan where the food isn’t sinking heat adequately get too hot.
"When comparing the tensile yield strengths of titanium and steel, an interesting fact occurs; steel is by-and-large stronger than titanium."
Many people confuse this issue, because they're actually talking about measures of strength/weight ratios, on which titanium does really well. But if you are size limited rather than weight limited, steel is often a better material than titanium even when cost is no object.
And anyway, your original comment suggested someone was totally in the wrong for thinking a 4mm titanium plate was strong, which is obviously incorrect. 4mmm of titanium plate is clearly going to be really strong and resistant. They wouldn't make plane engines from it if it wasn't.
...but they don't! Jet engines can only use titanium for certain low pressure, low temperature, sections. The high temperature parts are made from nickle/iron-based superalloys. And aluminum still gets significant usage, because for many geometries an aluminum part has a better strength/weight ratio.
Like I said, titanium is strong. But it's not magic. Stronger than any aluminum alloy, weaker than commonly used steel alloys. Hitting a 4mm plate of titanium with a hammer just isn't a very special experience. I've done it.
Hitting a 4mm tool steel plate definitely can be a special experience. Because it's so strong and hard that you could easily cause the thing to shatter, sending sharp shards in unpredictable directions...
Titanium has excellent strength to weight properties compared to steel. A 4mm titanium plate would absolutely be dented by common shop hammers. This doesnt mean that "titanium isnt strong" it just means they have different material properties.
AR500 has a HRC of 47, modulus of 220 GPa, and tensile strength of 1740 MPa. Ti-6Al-4V is 37, 113.8 GPa, and 880 MPa respectively. The AR500 costs less than half as much as the Ti, and is much easier to work (though obviously working will degrade the properties).
The titanium is super really light, however... so the choice of material will depend on how relatively important weight is vs size and how simple your geometry is such that the added difficulty in working with Ti doesn't add problems.
Obviously there are also other grades of Ti too, but I think the comparison generally holds: If you don't care about weight/mass there is a steel selection which will be stronger, cheaper, and easier to form.
If you do care a lot about weight, an aluminum alloy often comes out the winner unless you just don't care much about costs or have fatigue concerns.
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 corrosion resistant.
4340 steel isn't exotic. It's one of the most commonly used grades of steel out there, and it's much cheaper than titanium. There are steels out there with significant stronger yield strengths too. Meanwhile the highest yield strength of any Ti alloy is <1300MPa.
Titanium is still a really great material in certain applications. But it's not magic. You have to use it intelligently in the right application to get a benefit from it.
> "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.
>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.
The others mine molybdenum as a byproduct of copper. I guess you could say the Bagdad mine has a company town, but it wasn't made to secure the military supply chain 140 year ago.
[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.
When you go to both maximum cold (cryo fuel), and you go to maximum (reentry heat) then steel is amazing.
Aluminum would turn to butter on reentry, it would require a massive amount of heat shielding. Titanium alloys would have same issue.
Titanium alloy also become to brittle in deep cryo.
So steel beats everything in this demanding application. Its amazing.
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 they otherwise would be. Which makes very lightweight metals like magnesium and aluminum the better choice, as you can make thick parts at the required dimensions at very little weight.
Climbing gear is a great example of this. Even though there's a segment of that market for which money is no object, the only use for titanium in climbing gear is certain specialized applications where corrosion resistance is important. Eg fixed gear mounted on sea-side cliffs. Because climbing gear has to have certain minimum dimensions to avoid damaging ropes, the very low density of aluminum wins over titanium's higher density/higher strength.
If you made a carabiner out of titanium it'd be stronger than necessary, and a lot heavier.
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.
In terms of (rigid, diamond-frame) bicycles, this is why I’m still firmly in the steel camp. No aluminium, no carbon; just steel. It really does have an excellent combination of nice ride quality, low weight, high strength, good failure mode (I’ve broken a few frames, and they tend to just bend/sag, vs the rapid unscheduled disassembling of carbon/Al).
As a slight aside, magnesium is also a very interesting material. It might be we're on the cusp of a major expansion in magnesium usage due to recent advancements
- Mining from seawater (about 1 kg Mg in 1000L of seawater), or existing brine tailings from other extraction activities. With cheap solar electricity this might drive the cost down considerably (below the extremely dirty production methods being used today in China), providing carbon-emission free production of essentially unlimited amounts.
- thixomolding, a die-casting / injection molding-like process where the material isn't completely melted (thixotropic state), producing parts with much less porosity than traditional die casting.
- New alloys that are less prone to fires and corrosion.
For slightly more details, see https://www.youtube.com/watch?v=OIv_Rfl0L_A
For those curious, titanium is present in sea water, at 1 ppb! (magnesium is 1300 ppm)
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.
https://www.apple.com/newsroom/2023/09/apple-unveils-iphone-... https://www.youtube.com/watch?v=S_W73ouKtjU&t=605s
Thick walls on the iPhone are what are going to prevent X Y area which I suspect they need more than thickness.
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.
Indeed, if your design goal is strictly "don't get dented when hit by a hammer", the "strongest" material could easily be a good synthetic rubber!
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. And that in turn means that aluminum bike frames don't have as much of a weight advantage over steel as you'd expect.
Not directly extruding it, but the end result is metal.
But complex microstructures can be designed to have non-sudden failures. Eg. you could ensure that a visible crack appears at 0.75x the ultimate strength, yet doesn't fail till 1.0x the strength.
You can also design structures so that a 'crack' is either 1mm wide or not there at all (ie. no hairline cracks).
such features of microstructures are not free though - you will lose strength/weight to get them.
Bicycles don't have the minimum size problem GGP is talking about. Titanium is pretty much the perfect frame material (if you can afford it) - all the nice things you list (a bit stiffer than steel, but ride quality is still decent), but substantially lighter.
They do, in a slightly different way. Bicycle frames are (broadly) stiffness-critical structures. Wider-diameter tubes have a higher specific stiffness because of the increased moment of inertia - that's why we use structures like tubes and I-beams instead of solid bars. Steel frames have skinny tubes, because they're limited by the minimum wall thickness of the tubing; increase the diameter too much and you have a tube that is very vulnerable to dents and very prone to buckling. Steel racing frames of the 1970s are remarkably flimsy, because framebuilders were pushing wall thickness to the absolute limit.
Aluminium bicycle frames are only lighter because the lower density allows you to retain an acceptable wall thickness on larger-diameter tubes. An aluminium frame with the same tube diameters as a steel frame would be considerably heavier than the steel frame, because an aluminium frame needs to be overbuilt to compensate for the lack of a defined fatigue limit.
All common steel alloys have essentially the same stiffness (~207GPa), but higher-strength steels allow us to use wider-diameter tubes with thinner wall sections; incidentally, this is why it's quite pointless to use an expensive tubeset in a lugged frame. CFRP obviously has immense specific stiffness, but it also allows frame designers to really optimise the geometry and use the material more efficiently.
Titanium is a really nice frame material, but it does have some significant issues in practical use. Titanium is very prone to embrittlement if there is any amount of contamination in the weld. Most framebuilders aren't capable of maintaining the level of cleanliness and the comprehensive gas purging required to produce really good welds in titanium, so it's very common to see titanium frames eventually crack around the welds.
To my mind the perfect material for a non-sporting frame was the superb Reynolds 953 maraging steel, but unfortunately it is no longer available. Reynolds 931 and KVA MS2 are still very good materials, particularly when fillet brazed rather than welded. CFRP obviously wins out in terms of pure performance, but I'm not sure that I'd ever trust an old and battle-scarred carbon frame on a hard descent.
Good point.
> Titanium is pretty much the perfect frame material[…]
Anecdotally - I understand it’s tougher to work with at about every single step. I’ve seen too many cracked Ti bikes/parts to sign up, I think. I understand the lust though.
One advantage that adds to the potential lightness of aluminum and carbon fiber bike frames is manufacturing method. Aluminum is cheap to machine and hydroform into efficient shapes, and carbon fiber can also be layed up into efficient shapes.
Surly makes (only) steel mountain bikes, and I think there are approx. a... there's a lot of them out there. One reason is that they are inexpensive (relatively) and take a lot of abuse.
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...
Get a child trailer and load it up with groceries or cement! i tried it, the results are.. Surprising