Posted on 04/18/2016 12:15:38 AM PDT by 2ndDivisionVet
Back in 2011, we wrote about a fascinating new way to heat-treat regular, cheap steel to endow it with an almost miraculous blend of characteristics. Radically cheaper, quicker and less energy-intensive to produce, Flash Bainite is stronger than titanium by weight, and ductile enough to be pressed into shape while cold without thinning or cracking. It's now being tested by three of the world's five largest car manufacturers, who are finding they can produce thinner structural car components that are between 30-50 percent lighter and cheaper than the steel they've been using, while maintaining the same performance is crash tests. Those are revolutionary numbers in the auto space.
Graph demonstrating Flash Bainite's specific and tensile strength compared to aluminum, hot stamp steel and titanium Flash Bainite floor reinforcement part Compared to other ductile steel that can be formed at room temperature, Flash Bainite can deliver ... Compared to other high-strength hot stamp steel, Flash Bainite can deliver cost savings up to 50%
Darren Quick did a good job explaining exactly how Flash Bainite is produced in our original story, but in basic terms, you take regular, off-the-shelf AISI1020 carbon steel, and instead of heat treating it for 10 minutes like costly alloyed steel, you put it through a roller-driven system that induction-heats and liquid-cools the steel in a matter of 10 seconds or so.
Generally, when you choose steel you're trading off between strength and ductility. The hardest steels are the martensitic types, but their crystalline structure makes them brittle and prone to cracking when you press or bend them, so they need to be hot pressed. Flash Bainite breaks this rule by delivering a specific strength some 7 percent higher than martensitic steel but staying remarkably bendable to the point where it can be cold pressed into shapes. The quick heating and cooling stages produce a unique mix of fine martensite, bainite and carbides – if you want to get all metallurgical about it, knock yourself out.
With such characteristics, you could theoretically take anything you're making out of martensitic steel and make it stronger and vastly cheaper, or take many shapes you're cold pressing out of more ductile steel and use vastly thinner Flash Bainite to get the same strength. It sounded almost too good to be true, but recent testing from a number of different parties appears to be validating the original findings.
In July 2011, US Army tests called it "an extremely energy efficient and environmentally friendly process" and concluded that "the costs to produce Flash Bainite should be extremely reasonable and could enable widespread use for applications requiring very high strength and adequate elongation, ductility, and toughness. Current opportunities for flash bainite include armor and vehicle applications requiring ultra-high strength steels for high specific strength, weight reduction, and high cycle fatigue enhancement."
In 2013, a few auto manufacturers (who can't be named due to NDAs) began running a series of tests to see how Flash Bainite might perform in an automotive setting. Could it be cold pressed into the kinds of challenging shapes required by automakers? In short, yes. Flash 1600 (Flash-processed AISI1020) forms as well as the leading cold-stampable "advanced high strength steel" DP1180 that's only 75 percent the strength. Here are some sample parts displayed in March 2015, cold pressed with no noticeable thinning:
These parts were created in the same sizes and thicknesses as the OEM parts, so there's no weight saving per se, but the simple and energy-efficient nature of the Flash forming process makes them 1/3 to 1/2 less expensive than the process currently used in manufacture.
As this data became available, other auto manufacturers have started dipping toes in the water as well. The Flash Project's Gary Cola tells us of another major manufacturer that used Flash processed tubing to create car door impact beams, roof rails and other parts that were built into full cars, then roof crush tested to high test results.
"This OEM found that Flash 1500 could offer a 1/3 mass reduction and cost savings over the 'industry standard' DP1000 known at the time to be the strongest hydroformable tube," Cola says. "During this development, it was discovered that Flash 1500 (Flash-processed AISI1020) could be formed into very tight bends, almost as tight as simply folding a sheet of paper."
In Flash 1500 energy absorbing crush in this story's lead image, the bends are twice the strength of the DP780 cans in cars today.
Another major manufacturer "that makes 10 million vehicles per year," according to Cola, tested Flash-processed steel on a structural/safety component of a car that is 3 mm thick and 3 lb (1.4 kg) in weight in its current form. Using the flash treatment, a part was created that weighs 2 lb (0.9 kg) at 2 mm thick, and passes all the same tests – and the OEM estimated it could be made at a cost savings.
There are only three OEMs that can claim that kind of manufacturing capacity in the world. Only one of them is headquartered in Detroit where the Flash Bainite team is based, and it conveniently happens to be locked in a war of words with a competitor that has chosen to go to aluminum truck bodies instead of steel. Cola notes, "while aluminum is good for hoods, decklids and door skins, Flash offers higher strength per pound for structural safety components."
In short, Flash Bainite is starting to look suspiciously like the real deal, pointing the way towards significantly lighter cars that are less expensive and more environmentally friendly to produce, and every bit as safe in a crash – and of course, that's just in the automotive world.
Another factor in Flash's favour is an extremely low capital cost of entry for companies looking to get involved in the manufacturing process.
"The entry point for Flash equipment is about US$300K and a one car garage, while large format equipment would only cost $5M to generate about $75M in annual sales," Cola tells us. "Imagine if 100s of fabrication shops around the country could make higher performing steel than the Big Steel Industry can in their $400M seven-story tall furnaces."
Having said that, there's currently no large scale manufacture up and running. Cola and the Flash Project team are working toward developing their own commercial manufacturing operation, but hoping to license the Flash technology to other entrepreneurs to get it out into the market. If the business side is managed well, this looks like a genuinely disruptive shift in manufacturing. We'll keep an eye on it!
Interesting. I’ve sent this to my son, the metallurgist. Thanks for posting.
I’m curious as to the corrosion resistance if any.
I read about this in Atlas Shrugged.
Reardon Metal?
I’m confused...what does this article have to do with Ted Cruz?
If this pans out, the U.S. Steel industry will be revitalized. Thanks for posting this.
“I’m confused...what does this article have to do with Ted Cruz?”
Apparently there is some controversy about the poster being a paid operative of Cruz (who knows?), and the suggestion would be that paid operatives, having little credibility, try to throw in some neutral sounding stuff to misdirect from the mercenary nature of the agency.
Stronger, lighter airplanes perhaps?
I'd like to compare it too:
* 4130 Chromemoly
* The Structure of steels after Cryogenic processing
* And, Austempered Ductile Iron (ADI) which has a weird niche of a being a decent casted crankshaft material.
ADI is not Bainite read this from the link prvided: "The preponderance of information on the austempering of steel and the superficial similarities between the austempering heat treatments applied to steels and ADI, have resulted in comparisons which are incorrect and damaging to the understanding of the structure and properties of ADI. ADI is sometimes referred to as "bainitic Ductile Iron", but correctly heat treated ADI contains little or no bainite. Bainite consists of a matrix of acicular (plate-like) ferrite and carbide. ADI’s ausferrite matrix is a mix of acicular ferrite and carbon stabilized austenite. This ausferrite may resemble bainite metallographically, however it is not because it contains few or none of the fine carbides characteristic in bainite. An ausferrite matrix will only convert to bainite if it is over tempered."
http://www.ductile.org/didata/Section4/4intro.htm#Crankshafts
I wonder with this process if they are almost nitriting with the heat ( total thickness however ) and then almost cryo-ing with the water bath.
Interesting, and yes Aircraft applications would be interesting...
Always a major issue to deal with. Not much value to a super strong & light steel with a very short lifespan of structural integrity due to corrosion!
Since we are living through the rest of Atlas Shrugged, we might as well get Reardon metal.
“Always a major issue to deal with. Not much value to a super strong & light steel with a very short lifespan of structural integrity due to corrosion!”
Automotive steel is covered with anti-corrosion coatings. Remove them, and rust will ensue. I don’t believe any steel in current automotive use is particularly corrosion resistant.
It sounds as though the Army is on board, and its requirements are likely much more stringent than those of automakers.
Sure sounds like it doesn’t it?
In other words, the steel is lighter and stronger pound for pound, but your car won't necessarily be stronger -- or safer. It'll only be lighter.
I think one of the reasons grown-ups prefer heavier vehicles in the first place is their perception that a heavy vehicle is safer than a light vehicle in a collision.
Great news for racing, though. And with any luck, car prices will slow their race to the stratosphere.
Cool.
Does it still rust?
Here in the NE It would rust through by Christmas.
Heat, then cool.
Little heat treating joke for you.
L
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.