New steel treatment could enable lighter, stronger, cheaper cars (2015)
newatlas.com
newatlas.com
http://www.nextbigfuture.com/2016/07/japan-making-steel-20-3...
That said, neither is quite like this flash bainite. Both are very hard steels, so manufacturing and fabrication techniques need to suit the steels at hand. For example, machining the steels I listed can be very difficult and murders tooling bits compared to machining mild steel. Welding can also be difficult and usually involves significant preheating and post-weld heat treatment processes. Flash bainite apparently has some benefits in those areas but to what extent is hard to quantify.
I'd love to know more about this flash bainite process, but their website is really scant on details. Other sources of info suggest that you weld the structure together then flash process it afterwards, which I'd assume is completely useless for anything with complex geometry or substantial size. A military report [3] of its performance shows that welding after FB treating literally halves its strength, as you'd expect since the heat of welding is basically like traditionally heat-treating it over longer durations. In that sense the ones I mentioned are better because you can more slowly heat treat them post-welding via more flexible methods that can deal with more complex shapes. This lets you get restored strength properties because those steels aren't reliant on a flash-style process.
Where I think this reigns is in its ability to be formed easily whilst still being strong. Forming those steels I mentioned is a nightmare. In that sense it would certainly have applications where you can fabricate via fastening (rivets, bolts, etc.) but it seems to fall short when you need to weld it into anything more than a small butt-weld of two sheets.
Certainly an interesting development and I'd love to see it realised to a commercial product as it'd definitely have some uses, but it's not the be-all-end-all holy grail of steel.
[1]: http://www.bisalloy.com.au/
The big win for me is the parts can be air quenched - the slower cooling eliminates one of the biggest rejection flaws, straightness
For example, when I deal with the castings I procure, we mandate that the supplier either repairs them prior to the heat treatment stage or they must be fully heat treated again after weld repairs. This helps resolve the otherwise brittle HAZ. You can do this, because castings are usually quench-and-tempered, which is a relatively slow process.
Welding stuff like Bis, Weldox, etc. requires both pre- and post- heat treating in order to let the weld form and also address the HAZ properly afterwards to restore its strength. You can do this because the processes to heat treat it are traditional and relatively slow. This lets you get (somewhat reduced compared to the parent metal) structurally sound levels of strength out of the weld locality. Because of it, Weldox and Bis both see widespread use in truck bodies, crane arm trusses, etc.
This is in constrast to flash bainite, which relies on it being a very fast process. By virtue of it being a fast, tailor-made process you can't just do it to a complex geometry. By welding it, you dump heat into the weld which then air-cools slowly as the weld cools, completely running counter to the flash bainite process that is necessary to produce the strength. That's why you see a halving in UTS in the mil report I linked in source 3 of my first post - you simply can't recover from the slower heat-and-cool process without doing the whole treatment again, and you can only do that on easy geometries (it seems).
As said, if I understand what you're saying we're essentially saying the same thing, but I think I phrased it quite badly in my post. Not that you disagree with me, but it just made me realise that I don't think I worded it well and wanted to clarify.
For reference, bainite has completely replaced 8630 in all ranges of quenching and tempering as a material for us, and I'm currently in the process of phasing out most of our Hardox parts in lieu of bainite as well. Haven't used Bisalloy plate for years due to its even-worse-than-expected machinability.
Basically it is a fantastic material and I want to marry it.
So if you worked really really hard you might be able to do stuff that's 1/4" or maybe even 1/2" thick but it'd probably never work for 6" thick.
Yes they're focusing on tube because that's where it can be done. But if you could get very thick steel that's also stronger than Ti, that'd be AWESOME. Which is why I'm a little disappointed. This stuff isn't unobtanium, but it is a bit magical.
How many more opportunities are the out there just sitting in front of us, unconsidered?
In many cases, when metal gets stronger it becomes more brittle and less ductile, but this is not a fundamental relationship, in most cases it is an unwanted by-product.
For instance, seat belts absorb the energy instead of the body flying through a window, crumple zones increase the time it takes to push the energy into a seatbelt (which decreases the force and thus the damage).
[1] Hammer a piece of glass vs a piece of rubber.
Note that the metals under discussion here have very high strength (~1000-2000 MPa) and relatively little ductility (~10%), but are more ductile than other materials with this strength. On the other hand there are very ductile alloys that can tolerate 50% elongation and have strengths around 1000 MPa. These are achieved by adding basically a shitload (20% or more by mass) of manganese.
"while aluminum is good for hoods, decklids and door skins, Flash offers higher strength per pound for structural safety components."
So no more "like a mfg submarine" commercials or will they start making submarines out of it too?
I've just been chatting with a mech-eng materials specialist friend of mine, and according to him, you hit it, right there; he writes hot work will cause the microstructure to revert to classic regular BCC ferrite which isn't that impressive. that's the reason why you can't / shouldn't weld the stuff... ...essentially it's a "cast/quench this part and leave it the hell alone" material.
I'm a keen cyclist and some of the new steel frames are incredibly, they approach the same weight as aluminium frames with higher strength, better rigidity and they have (looked after) a basically indefinite lifespan.
I think my next bike will probably be steel.
Not long after I got it, it seemed that steel frames became totally passé; everything went to aluminum, titanium, and then carbon fibre. These days, road bikes all seem to be either aluminum or CF. And now history repeats itself...
Personally, though, I'm looking forward to ditching it and getting a recumbent trike. I'm getting sick of having a sore neck and shoulders and hands and having my arms go numb on long rides.
That said if you are having real numbness problems switching up to a 25mm tyre (most road bikes will take them) and running at 80psi vs 23mm at 110psi will make the most difference.
It also depends on the surface you ride on, UK roads are not known for been particularly smooth (particularly rural two lanes) so the differences are more marked.
https://patents.google.com/patent/WO2008042982A2/en seems to be the Flash Bainite patent application; if I'm reading this right, he's applied for a patent in the US and Canada, but neither has granted the patent after ten years.
Note that Flash Bainite is a different material than bainite; Flash Bainite contains bainite crystals, but also contains crystals of other phases, including (in the case of AISI 4130) 82.5% martensite. Bainite as such has been known since the 1920s. I'm not completely clear on whether _sammcf is talking about this kind of flash-processed steel in their comments or about some other kind of steel in which bainite plays an important role, though it sounds like they're talking about this stuff.
Putting the Rearden-Steel-like claims he makes in https://www.galtsgulchonline.com/posts/c0a47/hi-my-name-is-g... in context (thanks NamTaf!), the 2080 MPa strength he's claiming there is within a stone's throw of thin music wire, which is far and away higher than that of any other steel. But there's a huge difference in that the 10% elongation at break he's claiming is truly astounding — more like a plastic than a metal. Normal steels break at about 1% elongation, aluminum typically around 3%. Nylon 6,6 is typically around 30%.
The ASM HTPro article http://www.asminternational.org/documents/10192/17082024/Pag... says they got UTS of 1.99 GPa and 10.2% total elongation for "flash processed AISI 4140". I'm not sure yet how much of that elongation is plastic, though judging by the OP's photo of the crumpled thing, maybe most of it.
Bringing those two facts together, it would seem that it's substantially less stiff than ordinary steels, which means that even if all the claims are true, it won't replace them in uses where stiffness matters more than strength — uses like compressive structural members. Furthermore, the strengths discussed so far are ultimate stresses (after plastic deformation is exhausted), not yield stresses (stresses from which the steel will spring back), which may be unspectacular.
In short, it's not a better steel. If these claims are true, it is in effect an entirely new class of material, that just happens to be made out of steel.
Since you reach the Flash Bainite state by quenching, it seems likely that it's metastable and will eventually decay back into a more ordinary steel, but that's true of austenite too — for human applications, metastability is as good as stability if the time to relaxation is measured in billions of years.
I can't find any coverage of it in any authoritative news sources.
If you google the address given on the company's website, it points to "Sculptors Fitness Center".
Does any one have any knowledge to suggest that it's anything other than a hoax?