Flash Bainite Process
Cola, Gary
A lecture given by Gary Cola, at the Adventures in the Physical Metallurgy of Steels (APMS) conference held in Cambridge University. Presents the enticing story about the very rapid processing of steel to produce bainitic microstructures in milliseconds.
 Alright, well our final speed is about All right, well our final speaker of this morning's session is Gary Kohler. Now, Mr Kohler is a pioneer in the development of a steel that can be transformed to bay night in 100 milliseconds. So Professor Rong Shan Qin, I think you have competition for your pulsed steels. We shall see which one is more exciting and adventurous. My name is Gary Kohler. I've developed the flash bay night process for steels. And I'd like to acknowledge first off Ohio State University, NSF IUCRC, Professor Suresh Babu and a team of three different master's students and a few other doctors that have helped us along. And also Hyundai KIA, North American Steel, and I think we'll talk about 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 dies for the automotive industry. And what had happened is always dealing with spring back, 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 spring back. As a start, I Googled and I found Harry Bidash'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 P. to I'm very grateful for accepting my offer to come to Detroit and review my process to make water quench bayonite, 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 master's students to me. And for the last seven years now we've had quite the adventure trying to define our process. And 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, 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. Maximum strength in steel, as I've read it at least, about 30 years ago worked by Tameda and Okabayashi and then also by Jung and Badesha 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% bayonite 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 bayonite 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 bayonite 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've found is that there are many transformations occurring in our cooling from 650 to 550 C and from 460 to 360 C and what happens is the 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 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 bayonite 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 1 megawatt induction unit, a 2,000 amp 480 volt electrical service that took us 6 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 210 ton cooling tower on eBay as we did with our 1 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 3 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 percent of the time, we're seeing panels that are this flat right out of the machine. 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 percent bayonite, 80 percent 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-beam, C-channel or angle iron. The process is very simple. I've been using this cartoon since I went to Kyoto and met Heria 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 US Patent Office we now have novelty. We were just issued our first foundational patent on July 9th and I'll remember that number forever. 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. Where that leads us then is what we can do with other common steels and we've worked with things like 1008 steel at.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 this with higher specific strengths and more ductile than titanium 64 STA bar. So titanium at 25 dollars 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. What their conclusions after a six month study was that the novel flash break 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 Brinnell 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 will stop fragmentation. What we found with our flash bainite this is the velocity in feet per second and then this is the aerial density on kilograms per square meter of plate and what we've done is we've compared against titanium rolled homogenous armor high hard armor and aluminum and what we found is that at actually a lower aerial densities we can stop faster velocity bullets. Arm 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 aluminum. 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 a 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 GMAW 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.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 10-20 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 GMAW welding with six passes but also for other types of welding as well. Now you have to have civilian applications as well as defense applications and what we've been able to do is work with 4130 chrome moly tubing and with 25 millimeter diameter, 1.25 millimeter wall which is relatively thin wall tubing, we can get 80 degree bend radius is on a 1.25 millimeter center line 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 3 millimeter wall we're able to get 180 degree bends so essentially what we have is a method of chrome moly tubing that's been heat treated, 1800 mega pascals, 10 percent elongation, essentially triple the strength of standard chrome moly 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 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 5 meters per second and a maximum displacement of 200 millimeters and determined that 5 millimeters or 7 millimeters gave about the same results so I think they went with 5 millimeters in their drop test. And what they found is in comparison of door impact beams from 5 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 and 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 length or 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 and kilonewtons as you can see of the flash bayonite at 32 millimeters outperforms the boron 32, the flash bayonite 28's reasonably close. Interesting over here on total energy absorbed flash bayonite seems to start very, you know, 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 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 degree 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 degree 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% bayonite, 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 bayonite 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% bayonite 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 and partition? What's interesting is you would have all your low carbon bayonite 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 homogenized your steel this idea of heterogeneous austenite now makes all quenching processes novel again if you use the flash bayonite 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 Fort had his quad recycle so I have my first Baja vehicle but there's no dents, no dings, no damage on any of the flash bayonite 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 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 1000 degrees? Typically we heat to over 1000 degrees in less than two seconds so 500 per second is something reasonable. Our work has been from about 350 to 1000 degrees C per second whether we're using induction or direct flame and pinch. Don't you observe grain growth at this temperature because if you go very fast to high temperature normally you have kind of spontaneous grain growth about 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 414 our peak heating temperature is 1050 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. I'm sure this has something to do with the heterogeneous austenite and localized chemistries. And a very last question. Have you tried to study different initial micro structures before flash heating? I think it should be extremely important because it should influence the diffusional path of your carbide 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 spheridized micro structures with the 4130 and the 4140 because that gives us the maximum amount of ferrite present so that we can develop this upper bayonite 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 that can occur 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 flatness? Fire resistance? 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. Actually we have done some very preliminary work and found some exciting results because we have bayonite in the microstructure and what I read sometimes is that bayonite doesn't temper and reduce its strength. What we have 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 bayonite at 600 C is stronger than A36 is at room temperature. So now of course in architectural steels you are going to spray on your insulating coatings and things like that but we think that there is 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 have 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. Tanaris asks, do you have any info or estimation of the toughness at low temperatures? We have done fracture toughness and the fracture toughness as 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 are 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 presumably limited by the transfer. Right now the maximum thickness is essentially limited by the quenching rate. You can heat up steel with high powered induction and we are actually working with a company, Vio Helco in Greece that has interest in flash bayonite for tubing and that is one of their primary questions whether we can do bars or if we can just be limited to tubing thicknesses. Right now our thought is about 12.5 millimeters but I am sure there are 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 would like, as thick as you would 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 have been listening. I am joking. Alright. Thank you very much.
 Alright, well our final speed is about  All right, well our final speaker of this morning's session is Gary Kohler.  Now, Mr Kohler is a pioneer in the development of a steel that can be transformed to bay  night in 100 milliseconds. So Professor Rong Shan Qin, I think you have competition for  your pulsed steels. We shall see which one is more exciting and adventurous.  My name is Gary Kohler. I've developed the flash bay night process for steels.  And I'd like to acknowledge first off Ohio State University, NSF IUCRC, Professor Suresh  Babu and a team of three different master's students and a few other doctors that have  helped us along. And also Hyundai KIA, North American Steel, and I think we'll talk about  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 dies for the automotive  industry. And what had happened is always dealing with spring back, 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 spring back. As a start, I Googled and I found Harry Bidash'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 P. to I'm very grateful for accepting my offer to come to Detroit and  review my process to make water quench bayonite, 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 master's students to me. And for the last seven years now we've had quite the adventure  trying to define our process. And 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, 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.  Maximum strength in steel, as I've read it at least, about 30 years ago worked by Tameda  and Okabayashi and then also by Jung and Badesha 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% bayonite 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 bayonite 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 bayonite 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've found is that  there are many transformations occurring in our cooling from 650 to 550 C and from 460  to 360 C and what happens is the 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 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 bayonite 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  1 megawatt induction unit, a 2,000 amp 480 volt electrical service that took us 6 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 210 ton cooling tower on eBay as we did  with our 1 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 3 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 percent of the time, we're seeing panels that are this flat right  out of the machine.  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  percent bayonite, 80 percent 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-beam, C-channel or angle iron. The process is very simple.  I've been using this cartoon since I went to Kyoto and met Heria 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 US Patent Office we now have novelty. We were just issued our  first foundational patent on July 9th and I'll remember that number forever.  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.  Where that leads us then is what we can do with other common steels and we've worked with  things like 1008 steel at.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 this with higher specific strengths and more ductile  than titanium 64 STA bar. So titanium at 25 dollars 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. What their conclusions after a six month study  was that the novel flash break 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 Brinnell 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 will stop fragmentation. What we found with our flash bainite this  is the velocity in feet per second and then this is the aerial density on kilograms per  square meter of plate and what we've done is we've compared against titanium rolled homogenous  armor high hard armor and aluminum and what we found is that at actually a lower aerial  densities we can stop faster velocity bullets. Arm 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 aluminum. 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 a 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 GMAW  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.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 10-20 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 GMAW welding with six passes but also for other types of welding as well.  Now you have to have civilian applications as well as defense applications and what we've  been able to do is work with 4130 chrome moly tubing and with 25 millimeter diameter, 1.25  millimeter wall which is relatively thin wall tubing, we can get 80 degree bend radius  is on a 1.25 millimeter center line 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 3 millimeter wall we're able to get 180 degree bends so  essentially what we have is a method of chrome moly tubing that's been heat treated,  1800 mega pascals, 10 percent elongation, essentially triple the strength of standard chrome moly 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 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 5 meters per second and a maximum displacement of 200 millimeters  and determined that 5 millimeters or 7 millimeters gave about the same results so I think they  went with 5 millimeters in their drop test. And what they found is in comparison of door  impact beams from 5 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 and 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 length or 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 and  kilonewtons as you can see of the flash bayonite at 32 millimeters outperforms the boron 32,  the flash bayonite 28's reasonably close. Interesting over here on total energy absorbed  flash bayonite seems to start very, you know, 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 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 degree 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 degree  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%  bayonite, 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 bayonite 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%  bayonite 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  and partition? What's interesting is you would have all your low carbon bayonite 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 homogenized  your steel this idea of heterogeneous austenite now makes all quenching processes novel again  if you use the flash bayonite 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 Fort had his quad recycle  so I have my first Baja vehicle but there's no dents, no dings, no damage on any of the flash  bayonite 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 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 1000 degrees?  Typically we heat to over 1000 degrees in less than two seconds so 500 per second is something reasonable.  Our work has been from about 350 to 1000 degrees C per second whether we're using induction or direct  flame and pinch. Don't you observe grain growth at this temperature because if you go very fast  to high temperature normally you have kind of spontaneous grain growth about 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 414 our peak heating temperature is 1050 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. I'm sure this has something to do with the heterogeneous  austenite and localized chemistries. And a very last question. Have you tried to study different  initial micro structures before flash heating? I think it should be extremely important because it  should influence the diffusional path of your carbide 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  spheridized micro structures with the 4130 and the 4140 because that gives us the maximum amount of  ferrite present so that we can develop this upper bayonite 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  that can occur 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 flatness?  Fire resistance? 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. Actually we have done some very preliminary work  and found some exciting results because we have bayonite in the microstructure and what I read  sometimes is that bayonite doesn't temper and reduce its strength. What we have 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 bayonite at 600 C is stronger than A36 is at room temperature. So now  of course in architectural steels you are going to spray on your insulating coatings and things like  that but we think that there is 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 have 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. Tanaris asks, do you have any info or estimation of the toughness at low temperatures?  We have done fracture toughness and the fracture toughness as 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 are 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 presumably limited by  the transfer. Right now the maximum thickness is essentially limited by the quenching rate.  You can heat up steel with high powered induction and we are actually working with a company,  Vio Helco in Greece that has interest in flash bayonite for tubing and that is one of their primary  questions whether we can do bars or if we can just be limited to tubing thicknesses. Right now our  thought is about 12.5 millimeters but I am sure there are 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 would like, as thick as you would 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 have been listening. I am joking. Alright. Thank you very much.
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Alright, well our final speed is about All right, well our final speaker of this morning's session is Gary Kohler. Now, Mr Kohler is a pioneer in the development of a steel that can be transformed to bay night in 100 milliseconds. So Professor Rong Shan Qin, I think you have competition for your pulsed steels. We shall see which one is more exciting and adventurous. My name is Gary Kohler. I've developed the flash bay night process for steels. And I'd like to acknowledge first off Ohio State University, NSF IUCRC, Professor Suresh Babu and a team of three different master's students and a few other doctors that have helped us along. And also Hyundai KIA, North American Steel, and I think we'll talk about 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 dies for the automotive industry. And what had happened is always dealing with spring back, 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 spring back. As a start, I Googled and I found Harry Bidash'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 P. to I'm very grateful for accepting my offer to come to Detroit and review my process to make water quench bayonite, 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 master's students to me. And for the last seven years now we've had quite the adventure trying to define our process. And 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, 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. Maximum strength in steel, as I've read it at least, about 30 years ago worked by Tameda and Okabayashi and then also by Jung and Badesha 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% bayonite 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 bayonite 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 bayonite 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've found is that there are many transformations occurring in our cooling from 650 to 550 C and from 460 to 360 C and what happens is the 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 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 bayonite 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 1 megawatt induction unit, a 2,000 amp 480 volt electrical service that took us 6 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 210 ton cooling tower on eBay as we did with our 1 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 3 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 percent of the time, we're seeing panels that are this flat right out of the machine. 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 percent bayonite, 80 percent 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-beam, C-channel or angle iron. The process is very simple. I've been using this cartoon since I went to Kyoto and met Heria 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 US Patent Office we now have novelty. We were just issued our first foundational patent on July 9th and I'll remember that number forever. 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. Where that leads us then is what we can do with other common steels and we've worked with things like 1008 steel at.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 this with higher specific strengths and more ductile than titanium 64 STA bar. So titanium at 25 dollars 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. What their conclusions after a six month study was that the novel flash break 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 Brinnell 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 will stop fragmentation. What we found with our flash bainite this is the velocity in feet per second and then this is the aerial density on kilograms per square meter of plate and what we've done is we've compared against titanium rolled homogenous armor high hard armor and aluminum and what we found is that at actually a lower aerial densities we can stop faster velocity bullets. Arm 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 aluminum. 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 a 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 GMAW 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.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 10-20 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 GMAW welding with six passes but also for other types of welding as well. Now you have to have civilian applications as well as defense applications and what we've been able to do is work with 4130 chrome moly tubing and with 25 millimeter diameter, 1.25 millimeter wall which is relatively thin wall tubing, we can get 80 degree bend radius is on a 1.25 millimeter center line 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 3 millimeter wall we're able to get 180 degree bends so essentially what we have is a method of chrome moly tubing that's been heat treated, 1800 mega pascals, 10 percent elongation, essentially triple the strength of standard chrome moly 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 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 5 meters per second and a maximum displacement of 200 millimeters and determined that 5 millimeters or 7 millimeters gave about the same results so I think they went with 5 millimeters in their drop test. And what they found is in comparison of door impact beams from 5 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 and 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 length or 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 and kilonewtons as you can see of the flash bayonite at 32 millimeters outperforms the boron 32, the flash bayonite 28's reasonably close. Interesting over here on total energy absorbed flash bayonite seems to start very, you know, 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 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 degree 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 degree 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% bayonite, 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 bayonite 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% bayonite 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 and partition? What's interesting is you would have all your low carbon bayonite 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 homogenized your steel this idea of heterogeneous austenite now makes all quenching processes novel again if you use the flash bayonite 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 Fort had his quad recycle so I have my first Baja vehicle but there's no dents, no dings, no damage on any of the flash bayonite 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 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 1000 degrees? Typically we heat to over 1000 degrees in less than two seconds so 500 per second is something reasonable. Our work has been from about 350 to 1000 degrees C per second whether we're using induction or direct flame and pinch. Don't you observe grain growth at this temperature because if you go very fast to high temperature normally you have kind of spontaneous grain growth about 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 414 our peak heating temperature is 1050 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. I'm sure this has something to do with the heterogeneous austenite and localized chemistries. And a very last question. Have you tried to study different initial micro structures before flash heating? I think it should be extremely important because it should influence the diffusional path of your carbide 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 spheridized micro structures with the 4130 and the 4140 because that gives us the maximum amount of ferrite present so that we can develop this upper bayonite 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 that can occur 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 flatness? Fire resistance? 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. Actually we have done some very preliminary work and found some exciting results because we have bayonite in the microstructure and what I read sometimes is that bayonite doesn't temper and reduce its strength. What we have 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 bayonite at 600 C is stronger than A36 is at room temperature. So now of course in architectural steels you are going to spray on your insulating coatings and things like that but we think that there is 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 have 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. Tanaris asks, do you have any info or estimation of the toughness at low temperatures? We have done fracture toughness and the fracture toughness as 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 are 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 presumably limited by the transfer. Right now the maximum thickness is essentially limited by the quenching rate. You can heat up steel with high powered induction and we are actually working with a company, Vio Helco in Greece that has interest in flash bayonite for tubing and that is one of their primary questions whether we can do bars or if we can just be limited to tubing thicknesses. Right now our thought is about 12.5 millimeters but I am sure there are 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 would like, as thick as you would 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 have been listening. I am joking. Alright. Thank you very much.
microstructures occurring in the process. Now microstructure because if you look back at the inexpensive rapid process to improve the induction heating to take the steel to boron 3222, there's about the same resisting someone demonstrates the superiority of steel