The final speaker of this morning's session is Gary Kola.

Now, Mr. Kola is a pioneer in the development of a steel that can be transformed to bainite

in 100 milliseconds. So Professor Rongshan Qin, I think you have competition for your pulsed steels. We shall see which one is more exciting and adventurous. My name is Gary Kola. I've developed the flash bainite process for steels.

And I'd like to acknowledge first off Ohio State University, the NSF IUCRC, Professor Suresh Babu, and the team of three different masters students and a few other doctors that have helped us along, and also Hyundai Kia, North American Technical Center.

And I guess another thank you that I'd like to offer up is to a few people here in the room real quickly. My background is actually as a machine shop owner north of Detroit. I machine CNC stamping dyes for the automotive industry. And what had happened is always dealing with springback, I wanted to try

and develop a steel basically as a hobby that might have a little bit more ductility and a little bit less springback. As a start, I Googled and I found Harry Bedecia's name. And 10 years ago, I started reading his works, learned a lot, confused myself a little. And seven years ago, I contacted Matthew Pete, who I'm very grateful for accepting my offer

to come to Detroit and review my process to make water quench bainite, which sounds quite ridiculous if you think about it seven years ago. I met Suresh Babu a little later. And he actually assigned one of his masters students to me. And for the last seven years now, we've had quite the adventure trying to define our process.

And, you know, great thanks to Harry, Matthew, and Suresh because without the three of them inspiring and encouraging me, I wouldn't be here today. So a little bit controversial. Hopefully, you like what you hear. Okay, some unconventional thoughts on heat and quench.

Most of us have been taught that you need to homogenize your austenite. Really, when steel starts out in the ladle, we're at near homogeneity. Then when the steel is rolled, we go to the concept of heterogeneity of the ferrite, perlite, and carbides just in general terms. And then what would happen next is we would go back to homogeneity

in a continuous annealing line. And the question I have is, you know, but why do we want to go back? We have been taught that homogeneity is good. But there's also a lot of indications that heterogeneity, complexity can actually lead to very good things as well. Okay. Maximum strength in steel, as I've read it at least,

about 30 years ago worked by Tomita and Okabayashi and then also by Young and Bedesha, has shown that 100% martensite microstructure is not how you make steel the strongest. In these last 30 years, we've known that about 20% bainite

and about 80% martensite is stronger than pure martensite, roughly, let's say, 5 to 10%, but in any case, stronger for a given alloy. Now, flash bainite processing is essentially a method of extreme thermal cycling. If you look at a typical continuous annealing cycle, there's a longer time temperature history compared to the flash bainite thermal cycle.

What we attempt to achieve is temporal limiting of carbon migration and carbide dissolution. We do this for a reason. We have high intensity energy input because we need to control our austenite grain growth size. It's not our priority to refine our grain.

It's our priority to find the right grain sizes. We have a briefly elevated A sub 3 and that's due to the volume fraction of essentially 0% weight carbon in the ferrite because a majority of our microstructure starting out is actually ferrite. We work with this heterogeneous austenite and we quench it with extremely high driving forces.

Now, working with Ohio State University, they have something called single sensor differential thermal analysis and what we found is that we actually see transformations occurring in our cooling from 650 to 550 C and from 460 to 360 C.

And what happens is their transformation goes from endothermic to exothermic, endothermic to exothermic again, and at this point, we're transforming to one austenite daughter phase and at this point, we're transforming to another austenite daughter phase. What this indicates is that you actually have, although it's one bulk steel chemistry,

you have heterogeneous microstructures occurring in the process. Now, and tomorrow, Dr. Babu is going to go a little bit more into detail on exactly how this can occur in the steel and how we can get about 20% low carbon bainite in a martensite matrix. Today's application is going to be, today's focus is going to be more

on applications, both civil and defense. For starters, we're essentially self-funded. I have a 17,000 square foot machine shop north of Detroit and what we've done is we've built our own steel heat treating line. We have a one megawatt induction unit, a 2000 amp 480 volt electrical service

that took us six months to get installed in the building. We have 250 kilowatt tempering induction. We have a tempering furnace we built ourselves. We actually bought a 200 ton cooling tower on eBay as we did with our one megawatt induction unit. We bought for $20,000 on eBay even though it was brand new.

But we've built a 60 foot long processing line to do our flash processing. Currently, we're in pilot production. We're running at 22 to 24 kilograms per minute. We're making pieces of steel from alloy 4140 chrome moly that are 6.6 millimeters thick

61 centimeters wide and three meters long. And they are CMM certified flat within 1.2 millimeters right out of the process. We don't see a quench distortion. And if we do things wrong, I shouldn't say that. If we do things wrong, we can see many, many centimeters of curvature. When we do things right, which is about 99% of the time,

we're seeing panels that are this flat right out of the machine. Now a question, why consider flash bayonite processing? There's a lot of technology over many years from many great metallurgists that have worked with homogeneous austenite. Well, the first reason is because we've got this method

to heat treat heterogeneous steel to achieve 20% bayonite, 80% martensite. We have our pilot production line that's been proven on many, many hundreds of pieces of sheet and plate and tubing. And I've used the term maximum strength microstructure because if you look back at the idea that we're making steel

a little bit stronger than martensite, this isn't high strength. This isn't advanced high strength. It's not ultra strength. According to the data, it appears to be maximum strength. So if I'm wrong on that, please correct me. But what we have is an inexpensive rapid process to improve the mechanical performance of sheet, plate and tubing.

We're actually talking to customers right now about I-beams, C-channel or angle iron. The process is very simple. I've been using this cartoon since I went to Kyoto and met Harry and Suresh over six years ago. But we start out with a coil of steel. We feed it through rollers. We use a high intensity flame initially and now induction heating to take the steel to unconventionally high temperatures

and a few seconds later we quench in water. And that really is the heart of flash bayonite processing. One of the other interesting things is and I'm very proud to say after nine years of working with the U.S. patent office, we now have novelty. We were just issued our first foundational patent on July 9th

and I'll remember that number forever. So now one of the concepts of flash bayonite processing is that we heat to a little bit higher temperatures than most people. And what we found is that we actually gain better elongation by heating to these higher temperatures.

If we heat alloy 1010 to around 1010C, we end up with 720 megapascals and yield in 900 UTS. But if we heat to higher temperatures, we can find that we increase our yield strength and our ultimate strength. Now what we found is that there's a quote, just right peak heating temperature to achieve your maximum elongation.

Because here we are at 1100 megapascals at 8.5% total elongation just from common 1010 steel. Well, where that leads us then is what we can do with other common steels. And we've worked with things like 1008 steel at 0.04 carbon,

1010, 1020, 4130, and 4140. And what we've been able to achieve with the 4140 is almost 2100 megapascals, but still maintaining 10% A50 elongation. And this is at 97.2% iron. So this isn't a heavily alloyed steel.

We gain our strength and ductility purely from the microstructure, not by all the alloys that we put into it. Now I throw this slide in because I'm more application oriented as opposed to metallurgy oriented. And I've worked a lot in armor where I spend a lot of time hearing about how aluminum is lightweight or titanium is lightweight.

Well, the truth is you have to look at your specific strength. And I'm sure most of all of you know this, but on a pound per pound basis, HSLA really is not high strength. You know, aluminum is not lightweight. It's low density. And independent testing of flash bainite has found us with higher specific strengths and more ductile than titanium 64STA bar.

So titanium at $25 a pound could easily be replaced for many applications with steel, which is something people are much more familiar with working with, especially in this room here. Now we've been working with the US Army a little bit.

And Benet Labs Picatinny Arsenal did a study guided by the US Army. I call him the chief metallurgist. That's not his official title. But their conclusions after a six month study was that the novel flash bainite process for steels has the potential to reduce product cost and weight while also enhancing mechanical performance. We currently have a contract to develop what's called ultra hard armor

at 600 Brunel with the Army. For ballistics, they have two different types of armor. They have hard armor that stop projectiles. And then they have soft armor that'll stop fragmentation. What we found with our flash bainite, this is the velocity in feet per second.

And then this is the aerial density kilograms per square meter of plate. And what we've done is we've compared against titanium, rolled homogeneous armor, high hard armor, and aluminums. And what we found is that at actually lower aerial densities, we can stop faster velocity bullets, 30 caliber armor piercing bullets.

Now what was counterintuitive is that we had a good performing hard armor. You expected us to be poor performing against fragmentation. And there's a standard 20 millimeter frag simulated penetrator that flash bainite again had higher performance than titanium, RHA, and the aluminums. So we actually have a double win on this solution.

Now when you're working with armor, one of the first things you have to find out is can you weld this material? And working with Suresh and Ohio State and Edison Welding Institute, what we found is that typical high hard armor actually has fresh martensite and hardened brittle spots at the edges of the fusion line

when you weld it together with a six pass gma operation. The flash bainite, on the other hand, doesn't tend to have those hard spots at the edge of the fusion line. The theory for that is that this material, the high hard, is actually homogenized before it's quenched. It's actually 0.3 carbon everywhere

and has all of its alloys dissolved which can lead to brittleness. The flash bainite, on the other hand, because of the rapid thermal cycling, actually has a chemistry that is probably leaner than 1020 for the most part of it because we start out with ferrite that doesn't have time to have carbon migrated into it

and what happens is we have this low carbon bainite, a very lean chemistry in most of our flash bainite and maybe richer chemistry in 30 to 40 percent of it but now you have a more ductile weld occurring in this process. And this works not only for gma welding with six passes but also for other types of welding as well.

Now, you know, you have to have civilian applications as well as defense applications and what we've been able to do is work with 4130 chromoly tubing and with 25 millimeter diameter, 1.25 millimeter wall, which is relatively thin wall tubing,

we can get 80 degree bend radiuses on a 125 millimeter centerline radius. Now, for this tubing, that's about the maximum bend they try and do when they're building dune buggies or roll bars for vehicles with this thickness. Now, similarly with a three millimeter wall, we're able to get 180 degree bends.

So essentially what we have is a method of chromoly tubing that's been heat treated, 1800 mega pascals, 10 percent elongation, essentially triple the strength of standard chromoly 4130 but we're not getting outer diameter wall collapse at our bends. We're actually able to hold our structural integrity. These results led us to work with Hyundai Automotive

where they were working on automotive door side impact beams and what had happened is they had developed a test setup where they would drop an impactor on a door beam and they wanted to compare flash bayonite to other materials they'd been working with. They had set up a test stand with 320 kilograms impact velocity of five meters per second

and a maximum displacement of 200 millimeters and determined that five millimeters or seven millimeters gave about the same results. I think they went with five millimeters in their drop test and what they found is in comparison of door impact beams

from five highly rated current production vehicles. All of the impact beams were from boron hardenable steels from various steel mills and they also used a brand new boron steel of their own design. You can see what happens when these pieces are deflected 200 millimeters. You can see the force in kilonewtons that results and also the displacement that's occurring as the impact happens.

Now what they did is they took flash bayonite and the first comparison was boron 32 millimeter diameter at 2.2 millimeter wall stock and you can see the large variety of different diameters and different wall thicknesses that they checked with flash bayonite. Larger diameter tubing trends towards higher resisting force.

Thicker wall stock trends towards higher total energy absorption. Well an interesting thing they found out if you look at this magenta line of the boron 3222 there's about the same resisting force as the flash bayonite 2824 which is actually lighter per unit length

and yet we had more total energy absorbed even though we were at a smaller diameter. Now this led to charts on the flash bayonite versus the boron tubing on a per mass basis. The resisting force in kilonewtons as you can see of the flash bayonite at 32 millimeters outperforms the boron 32.

Flash bayonite 28's reasonably close. Interesting over here on total energy absorbed flash bayonite seems to start very excelling quite a bit because the 32 millimeter flash versus the 28 millimeter flash versus the 32 millimeter boron and you can see these are all at constant wall thicknesses.

Generally speaking the flash tubing has about 15 percent higher resisting force and about 20 percent more energy absorbed than boron tubing. Another notion of the flash bayonite is because of the bayonite in it is that we're able to heat to temperatures of 400 to 550 c cool to ambient and then you still have significant strength remaining.

The flash bayonite after heating to 400 c has about 23 percent elongation. At 500 c you get 30 percent elongation you know rough laboratory experiments. After cooling at 400 from 400 c you retain 90 percent of your prior strength

or 77 percent of your strength after cooling from 500 c. We've been talking to many of the auto OEMs or the OEMs and tier ones in metro Detroit about the concept of replacing hot stamped boron with a warm formed flash bayonite alloy that's been fully tempered reheatable for secondary options

and it's just it's an alternative to the high cost of boron steels. Now with the flash bayonite when you write a patent you write it for exactly what you're doing and you try and expand just a little bit so that you can discuss further changes in the future that make your patent a little bit better I guess. You know what we're doing right now is we actually take our material

and in a few seconds we heat up to somewhere over a thousand degrees centigrade depending on the alloy of steel. Substantially immediately we start quenching in water and bring the steel back down to room temperature. If you consider temperatures above 200 degrees centigrade

this is about a five second process. What we've done with our intellectual property is we've been able to put in the idea of an optional preheat and then if you start the clock at T0 whether your preheat takes 10 years or 10 seconds you're allowed five seconds to exceed a thousand C

and then you have to immediately initiate your quench. Now what's interesting is that we don't have to quench down to room temperature we just have to start quenching as soon as we reach our peak temperature which we think gives us a lot of latitude going forward. You know and again right now we're using the water spray

to get to 20% bainite, 80% martensite. Now what this does though is this leaves us options for the future. You know I'd like to think that the flash bainite microstructure can stand on its own as a technology but also if you look at the idea of think of the concept what happens if you heat rapidly

develop a heterogeneous microstructure you know from 650 C to 550 C you develop 20% bainite what could you do with that remaining 80% non-transformed austenite? Would you put it in a galvanizing quench? Would you put it in a salt bath? Would you possibly quench in partition?

What's interesting is you would have all your low carbon bainite formed up high low carbon martensite formed next and then you could have reasonably high enriched carbon non-transformed austenite maybe 0.4 or 0.5 carbon to work with down here and partition out.

I guess what I'm really getting at is a lot of good work has been done on homogenized austenite but the atomic interactions and localized chemistry after flash heating is an extremely new field of study. Because all prior quench patterns start out with homogenizer steel this idea of heterogeneous austenite

now makes all quenching processes novel again if you use the flash bainite heating thermal cycle. So we've actually got a new field of study basically an adventure if you will. Last picture here we've been working with Lawrence Tech SAE Baja vehicle for five years now college students have been weld fabbing this vehicle

and what's most interesting is the front of the A-arms I can't tell you the number of times at 35 miles an hour they hit boulders and rocks and tree stumps in the farmer's field but this vehicle is back in my building it's kind of like Henry Ford had his quadricycle so I have my first Baja vehicle

but there's no dents, no dings, no damage on any of the flash bainite material it's turned out to be extremely robust other than it makes the vehicle flip over quite often instead of bending and breaking. Conclusions, just what I've talked about and again if the biggest conclusion you know a thank you to Harry and Matthew and Suresh

because if it wasn't for the three of them I wouldn't be a metallurgist today, thank you. Well Gary thank you so much and I think I speak on behalf of everyone in the audience when we say thank you for once again demonstrating that we do work on superior materials I think we all enjoy feeling smug when someone demonstrates

the superiority of steel over titanium and aluminium so thank you for that. Now I'm sure you've got lots of questions. Thank you for the excellent talk it's amazing work which I see here and I think it's absolutely the right direction that possibly the technology should go in the next years because it has a lot of positive things this approach.

Just a question, so could you mention briefly what is the range of the heating rates that you use to reach this temperature at 1,000 degrees? Typically we heat to over 1,000 degrees in less than two seconds. So 500 per second is something reasonable.

Our work has been from about 350 to 1,000 degrees C per second whether we're using induction or direct flame impingement. Yep and don't you observe grain growth, outside grain growth at this temperature because if you go very fast to high temperature normally you have kind of spontaneous grain growth above certain temperature when you remove the pinning effect

of your carbide structures there. What we've actually found and I tried to exemplify that with the 1010 steel is that grain growth is not a bad thing with the flash processing and the heterogeneous chemistry we actually find that larger grains can be better. Working with steels like 1010 our peak heating temperature

could be somewhere in the neighborhood of 1200 degrees centigrade. Working with a steel like 4140 our peak heating temperature is 1,050 degrees C which then has lower grain sizes but for some reason we find we get better elongation with different grain sizes for different alloys of steel

and this I'm sure this has something to do with the heterogeneous austenite and localized chemistries. And the very last question, have you tried to study different initial microstructures before flash heating? I think should be extremely important because it should influence the diffusion of path of your carbon which in fact determines what happens there.

Yes absolutely correct. The idea of flash processing will work as long as there's ferrite present because what you need is you need the carbon gradient but we do get our best results with spheroidized microstructures with the 4130 and the 4140 because that gives us the maximum amount of ferrite present

so that we can develop this its upper bainite very low carbon ductile region to go along with the high carbon martensitic regions that also occur. Thank you very much. So I don't need to say it was a fantastic lecture if it is not a commercial secret

what goes wrong when you lose your flatness? You know what in the process gives you a bad flatness? There's actually two things you have to worry about. Most people talk about quench distortion but we actually find heating distortion to be an issue as well. So what you have to do is you have to maintain the same size grains

on both sides of the sheet of steel and that will help you to avoid the heating distortion but then also the quench distortion if you have a sheet of steel rolling in this direction and you're quenching at the same time top and bottom everything is wonderful. If the steel starts to float up a little bit and then you start hitting the top sooner

compared to the bottom then you end up quenching the top before the bottom and then that will cause your distortion. So there's actually mechanisms we have in place to make sure that we heat evenly and quench both the top and bottom at the same time. And if that doesn't occur the steel starts waving and then it hits the induction coil and hits the water spray and makes a very big mess.

So we try not to do that often. Gary, nice talk. Just one question. Did you try to see what is the fire resistance of the flash minute? Fire resistance? Because you are now talking about that it is retaining some of its strength at higher temperatures. So if you could just see what is the fire resistance

then it would be very nice. Oh, fire resistance. Okay, I'm sorry. Yeah, actually we have done some very preliminary work and found some exciting results because we have bainite in the microstructure and what I read sometimes is that bainite doesn't temper and reduce its strength. What we've found is that our material

at 600 degrees centigrade, the flash 4130 still has a yield strength of 45 ksi. Now we found that exciting compared to A36 material which is 36 ksi at room temperature. So an initial indication is that flash bainite at 600 c is stronger than A36 is at room temperature.

So now of course in architectural steels you're going to spray on your insulating coatings and things like that. But we think that there's some definite potential for material that has a better starting point for heat resistance right away. We haven't done any studies on creep resistance but some of the lectures I've seen here now

make me think that we need to flash process some 9 chromium steel just to see what happens. Okay, are there any questions from? Yeah, there are a couple from the internet. Tenaris asks, do you have any info or estimation of the toughness at low temperatures? We have done fracture toughness

and gosh, the fracture toughness has armor. I can't remember the results to be honest with you but I could provide them after. I know at room temperature our fracture toughness is 66 compared to 4340 which is at 50. So we're a third tougher than 4340 is and I know there were no difficulties in the armor testing

with ductile to brittle transition temperatures. And a final question. They ask about the maximum thickness you can go to which is presumably limited by the heat transfer. Right now the maximum thickness is essentially limited by the quenching rate. You can heat up steel with high powered induction

and we're actually working with a company Viohelco in Greece that has interest in flash bainite for tubing and that's one of their primary questions is whether we can do bars or if we can just be limited to tubing thicknesses. Right now our thought is about 12 and a half millimeters but I'm sure there's some equations that we can work through to determine just how fast

you can take the heat out of the steel. Obviously with induction you can heat it up as quick as you'd like, as thick as you'd like just with more megawatts. Thanks. Are there any other questions from the audience? Perhaps the speaker would like to ask you some questions to see if you've been listening. I'm joking. All right. Thank you very much.