A new way to make lighter, stronger steel -- in a flash

June 9, 2011 by Pam Frost Gorder, The Ohio State University

A Detroit entrepreneur surprised university engineers here recently, when he invented a heat-treatment that makes steel 7 percent stronger than any steel on record – in less than 10 seconds.

In fact, the , now trademarked as Flash Bainite, has tested stronger and more shock-absorbing than the most common titanium alloys used by industry.

Now the entrepreneur is working with researchers at Ohio State University to better understand the science behind the new treatment, called flash processing.

What they've discovered may hold the key to making cars and military vehicles lighter, stronger, and more fuel-efficient.

In the current issue of the journal Materials Science and Technology, the inventor and his Ohio State partners describe how rapidly heating and cooling steel sheets changes the microstructure inside the alloy to make it stronger and less brittle.

The basic process of heat-treating steel has changed little in the modern age, and engineer Suresh Babu is one of few researchers worldwide who still study how to tune the properties of steel in detail. He's an associate professor of materials science and engineering at Ohio State, and Director of the National Science Foundation (NSF) Center for Integrative Materials Joining for Energy Applications, headquartered at the university.

"Steel is what we would call a 'mature technology.' We'd like to think we know most everything about it," he said. "If someone invented a way to strengthen the strongest steels even a few percent, that would be a big deal. But 7 percent? That's huge."

Yet, when inventor Gary Cola initially approached him, Babu didn't know what to think.

"The process that Gary described – it shouldn't have worked," he said. "I didn't believe him. So he took my students and me to Detroit."

Cola showed them his proprietary lab setup at SFP Works, LLC., where rollers carried steel sheets through flames as hot as 1100 degrees Celsius and then into a cooling liquid bath.

Though the typical temperature and length of time for hardening varies by industry, most steels are heat-treated at around 900 degrees Celsius for a few hours. Others are heated at similar temperatures for days.

Cola's entire process took less than 10 seconds.

He claimed that the resulting steel was 7 percent stronger than martensitic advanced high-strength steel. [Martensitic steel is so named because the internal microstructure is entirely composed of a crystal form called martensite.] Cola further claimed that his steel could be drawn – that is, thinned and lengthened – 30 percent more than martensitic steels without losing its enhanced strength.

If that were true, then Cola's steel could enable carmakers to build frames that are up to 30 percent thinner and lighter without compromising safety. Or, it could reinforce an armored vehicle without weighing it down.

"We asked for a few samples to test, and it turned out that everything he said was true," said Ohio State graduate student Tapasvi Lolla. "Then it was up to us to understand what was happening."

Cola is a self-taught metallurgist, and he wanted help from Babu and his team to reveal the physics behind the process – to understand it in detail so that he could find ways to adapt it and even improve it.

He partnered with Ohio State to provide research support for Brian Hanhold, who was an undergraduate student at the time, and Lolla, who subsequently earned his master's degree working out the answer.

Using an electron microscope, they discovered that Cola's process did indeed form martensite microstructure inside the steel. But they also saw another form called bainite microstructure, scattered with carbon-rich compounds called carbides.

In traditional, slow heat treatments, steel's initial microstructure always dissolves into a homogeneous phase called austenite at peak temperature, Babu explained. But as the steel cools rapidly from this high temperature, all of the austenite normally transforms into martensite.

"We think that, because this new process is so fast with rapid heating and cooling, the carbides don't get a chance to dissolve completely within austenite at high temperature, so they remain in the steel and make this unique microstructure containing bainite, martensite and carbides," Babu said.

Lolla pointed out that this unique microstructure boosts ductility -- meaning that the steel can crumple a great deal before breaking – making it a potential impact-absorber for automotive applications.

Babu, Lolla, Ohio State research scientist Boian Alexandrov, and Cola co-authored the paper with Badri Narayanan, a doctoral student in and engineering.

Now Hanhold is working to carry over his lessons into welding engineering, where he hopes to solve the problem of heat-induced weakening during welding. High-strength steel often weakens just outside the weld joint, where the alloy has been heated and cooled. Hanhold suspects that bringing the speed of Cola's method to welding might minimize the damage to adjacent areas and reduce the weakening.

If he succeeds, his discovery will benefit industrial partners of the NSF Center for Integrative Materials Joining Science for Energy Applications, which formed earlier this year. Ohio State's academic partners on the center include Lehigh University, the University of Wisconsin-Madison, and the Colorado School of Mines.

Explore further: Welders can breathe easier with chromium-free alloy

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4.5 / 5 (4) Jun 09, 2011
How many other "mature" processes can be vastly improved with newly emerging control of microscopic granularity? One wonders.
2.5 / 5 (2) Jun 09, 2011
I wonder if this can translate into flow blown metallic glass?
1.6 / 5 (7) Jun 09, 2011
How many other "mature" processes can be vastly improved with newly emerging control of microscopic granularity? One wonders.

This sort of control has been exercised with steel for at least the last century and has been extensively studied and mapped. Either this process has truely been overlooked or it has been previously discovered and 7% wasn't worth "aggressive" processing at the time.
not rated yet Jun 10, 2011
What if we used lasers to gain even more control over the heating process? You could even have lasers that could rapidly cool the steel down as well. Probably a century away, and that is if carbon in general doesn't make steel obselete.
1.3 / 5 (3) Jun 10, 2011
How does this compare with the Australian product they call "paper" which is made of graphene and is as thick as paper and much stronger than steel, and naturally very much lighter.
Check with UTS Sydney Australia.
1 / 5 (4) Jun 10, 2011
Rearden Metal?
4.3 / 5 (4) Jun 10, 2011
Make sure it is fully documented and published then outsourced so that our foreign trade partners can then steal the IP and sell it at lower prices on the world market because they don't mind exploiting labor and degrading the environment.

Cynical? People wonder why our government has to keep business taxes so low so they can compete in the world economy, then complain about outsourced labor & production, then go to Wall-mart and buy a bunch of cheap "crap" from countries that uses near-slave labor and does little to enforce pollution control, and then think "somebody" has got to do something about rising levels of CO2.

The media needs to start pointing fingers at the public for their part, because the politicians aren't going to.
1 / 5 (1) Jun 10, 2011
As far as I know this is a new technique for strengthening steel, but the idea of fast welding and minimizing heat migration into the base metal of a weld to reduce weakening has been known for some time. Now, if a new, faster and better technique is developed that still provides adequate penetration into the base metal - that would be welcomed by industry.
4.3 / 5 (3) Jun 10, 2011
For ISELIN, we have worked with the best metallurgists in the world. Consensus is that Flash Processing defies all known steel transformation theory to controllably make bainite "left of the nose".

The 7% improvement in strength is just what Ohio State Univ found in their work on one alloy. We have made over 300ksi UTS steel at 10% elongation from 97% iron at 0.40%wt C. It is readily weldable at room temp and definitely not costly like superalloys. Considering pound per pound specific UTS, this is 14% stronger than Ti-64 STA BAR at 150ksi/8%elong and twice as strong as "lightweight" 6061 Aluminum.

We are fighting hard through an amazingly stubborn government bureacracy right now. We have test results that we had to pay for from the US Army that show Flash Bainite stops armor piercing rounds AND Fragmentation better than all other readily weldable metals. It's discouraging how slow they move when you put the solution right in their hands, but that's another story AKA Rearden!
2 / 5 (1) Jun 10, 2011
Sadly the military is not very "savvy", as the casualty rates at the beginning of most wars can attest.

But what the military *is*, is political. If you can contact some of the military advocacy groups and spread the word, that could help allot.

Make a website with the what and who and disperse the link onto FB. That will get some attention.

Just don't post the secret recipe ;-)

You should also consider selling some firing range targets. Small revenue but it's own kind of advertisement. My brother is always looking for more durable targets for the range he belongs to.

5 / 5 (3) Jun 10, 2011
How does this compare with the Australian product they call "paper" which is made of graphene and is as thick as paper and much stronger than steel, and naturally very much lighter.
Check with UTS Sydney Australia.

While the progress with graphene paper is encouraging, it is still very expensive, even compared with current carbon fiber technologies. By contrast, this flash heat treating process is both quicker, cheaper, and produces stronger steels than current heat treatments. It should also be very easy to implement on a wide scale quickly.

This is not to say that graphene paper won't be hugely important, just not yet.
4 / 5 (4) Jun 11, 2011
This is exactly the kind of thing for which process patents were invented. The guy who made this stands to make millions and rightly deserves so for "inventing" something new.

Much unlike software "patents" where people register patents for broad-sweeping ideas right out of thier ass and then sit on them for decades until someone else independently "invents" the same thing and actually goes about applying it to code.
5 / 5 (1) Jun 11, 2011
What amazed me is how they created a 2000MPa grade with so much elongation. Usually martensitic grades have about 5% TE. From what the article describe the so call "Flash Bainite" is not even tempered. My guess is that bainite forms a skeleton in the microstructure.
2 / 5 (3) Jun 12, 2011
Quick quenching has been known for a long time. It was how steel was originally hardened. This sounds exactly the same. I don't understand how it is different or how it hasn't been discovered until now. Rumor has it that swords were once quenched and hardened like this by quickly inserting hot swords into cool people.
2.3 / 5 (3) Jun 12, 2011
How does this compare with the Australian product they call "paper" which is made of graphene and is as thick as paper and much stronger than steel, and naturally very much lighter.
Check with UTS Sydney Australia.

Like apples and meteorites.
1 / 5 (1) Jun 12, 2011
Wretched system ate my long comment.

This is a huge advance in strength and workability and on both a strength per $ and a (strength/weight) per $ basis this should be unbeatable. I hope this is available immediately, I have some ideas for it.
not rated yet Jun 13, 2011
You can blame the military for not recognizing the attributes of your new material, but I suspect the lethargy has more to do with the fact that the the federal government has other priorities right now. Secretary of defence Gates has proposed lopping 400 billion dollars off of defence over the next 12 years. Not suprisngly, the FCS was cancelled, so I don't see any large armor aquisitions during most of your lifetimes. Of course, that depends on a lovey dovey world environment which looks less likely as the US abdicates its role as the world's dominant power. As Sanesscience was alluding, the Chinese will probaby just partner with the American firm developing this technology, steal it, make their own tanks using it, and sell it back to us in the form of exploding electric cars.
2.7 / 5 (6) Jun 13, 2011
What I really like about this article is this tiny little statement right here:
Cola is a self-taught metallurgist,

Shows that when you don't care about the limitations you aren't constrained by them....!
2 / 5 (1) Jun 13, 2011
The difference with this method is that it works with any low-carbon steel, and typically more than doubles the strength compared to the same alloy with regular heat treating. It works by heating the steel so rapidly that the carbon doesn't have time to dissolve before the quench. It uses less energy than conventional treatments, works on everything from plain 1020 to 4130 chrome-moly, can withstand some tempering, has ductility enough for stamping and bending, works well with sheet, pipe, plate, and structural forms from 0.035 inch to over 1/4 inch, and produces more uniform results than conventional treatment. Flash-bainite 4130 even has better strength to weight than aluminum or titanium alloys, while being much cheaper and easier to fabricate. If the licensing isn't too onerous, based on the fairly minimal energy and equipment required I'd expect this to add less than $100/ton to production costs for large amounts, perhaps 10% or less of current prices for a doubling in strength

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