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Okay, so I did find the part in the report. 4,694 [Liberty ships] flooded, see literally ships born to join [the war effort]. 970 of these vessels suffered casualties involving fractures, 24 vessels sustaining complete fracture of [the hull], one vessel sustained complete fracture at the bottom, eight vessels were lost or broken due to brittle fracture, 26 lives are lost. This is a fracture certain combination of low temperatures and seized by the law. Anyway, so their conclusions — yes. So was it because they were making more vessels, because they were making them in different ways, because they were in the North Atlantic which wasn't a normal travel, because we had different routes? Based on summary, I guess, why did they not — so why did they have problems? Such a surprise. Well, there are a couple of reasons.

One is they had never really welded ships before, okay. And it is — Quan Gan Wellman shows the first metal ship was like 1860, the battleship, portal liner for going across the ocean. We had the Monitor [and] Merrimack that were just bolted, you know, riveted sheets of steel on the wood bonding, right. And they did build this Great Eastern. The Great Eastern, it was all metal, but they built and all those ships in the 1870s. Then warships in the Spanish-American War were sealed with their ability — they didn't have welding technology.

Welding did not come about until we had a source, voltage source. And when was that? 1880s, with guys named George Westinghouse and concepts, okay. Arc welding was invented by Sir Humphry Davy in the early eighteen hundreds — 1805, 1806 — when he discovered the electric arc. And the reason it's called an electric arc, he had two probably copper electrodes that were horizontal, and if you — when he, he was using electricity from the Leyden jars and sort of battery or something, he pulled apart and he struck an arc. It was a little bit of flame, and but it had an arch because the rising gases created an arch. That's where the word "arc" — somehow they arc. And one of the first things he did with this new source was he welded, okay. But no one could do it commercially until the 1880s. And there's a woodcut, a lot of the welding books on history of welding shows a battery of Leyden jars in the background and a French woodcut showing people welding in the 1850s, 1860s by electric arc, blow. But really electric arc welding didn't exist in a big way until the early 1900s.

And there's a lot of work done by companies still — welding power supplies, arc welding power supplies — and then to develop what we call stick electrodes. This is actually part of one of the other ones we'll probably watch out video, but I might go tell you some of the district because I'd rather hear a question than my lecture. [Tom produces a stick electrode.] So this is a stick electrode. What happened is originally people had just been welding with the bare steel wire. Okay, the problem with the bare steel wire, what you mark well, is it picks up nitrogen from the air, and when it solidifies the nitrogen gets rejected, and the rejected nitrogen comes out and makes the weld porous. Looks like Swiss cheese. I mean not small pores, these two things size of the meter or something like that. And it's just a terrible weld. It has some strength, but it's not as strong as it should be, and it looks terrible on service.

So turns out two things happen. There's two types of electrodes. One guy in Gudov in Sweden, working for a company that's now part of what's called ESAB Corporation, found that he stuck his steel electrode — this is an early 1900s — stuck in the mud, and welded with a muddy electrode, the porosity went away. And that's the basis of what we call mineral coated electrodes. Now this is a 7018 electrode from common high-quality welding — more hydrogen. Kind of a cement white coating, flux on the surface. If you bend it, it will start cracking immediately, okay. But you bend it, see how it'll break.

Another guy in the United States — and we don't know, I don't know who this was — but he found if he wrapped it like rolled up a piece of paper, he could weld and he no longer got the nitrogen porosity. Didn't even know it was nitrogen porosity back then, but that's the basis of what we call cellulosic electrode. And that, a lot more important — starts cracking. That one's heated up about 350 degrees Fahrenheit, that was heated up to about 800 degrees Fahrenheit to drive the moisture off, okay. This one full of moisture. They make it out of paper, actually they don't make it out of paper — Lincoln Electric uses old tobacco stocks as their form of cellulose. This is proprietary information. I got it out of the gutter, okay. How do you get it from Lincoln, but I'm told they use old tobacco stocks. I got it from one of Lincoln's competitors, okay, who was just telling a story once. Because tobacco concentrates the rubidium from the soil. And rubidium being in the first column of the periodic table — rubidium being a first-column-of-the-table, gives up electrons much easier than sodium and potassium, okay. And so what could be cheaper than old tobacco stocks which have no other use, okay. And you get a cheap source of rubidium too, which helps the arc stability. So there is some science to it.

But in any case, in nineteen hundred, people learned to make stick electrodes, but they still didn't have really good quality welds. And in World War I, there was a professor at Harvard named Comfort Avery Adams. He was known as the dean of American engineers, and as we entered the war he was put in charge of the American Emergency Fleet Corporation, which is a new part of the federal government to build the ships to get the boys over there. Couldn't fly them, okay, we had to float them, okay, well they could go to the shows. But Comfort Adams was actually at one time, this electrical engineer, and he worked on building welding power supplies first in his career. And he realized after the war they had never been able to weld the ships because they didn't really have the technology. So he decided in 1921 to form the American Welding Society. He was the first president of American Welding Society. He gave the Adams Lecture — who's the first AWS, kind of named after himself — but the society, he was the leader of American Welding at the time.

Well, they didn't build a critical structure by welding until the early 1930s. They built the deep-inch pipe walk — this was Louisiana up to New Jersey, 30-inch diameter. Now they had pipelines before, but they were lap-seam overlap and very intensive. I mean, they didn't have all that riveting guns, they had people with hammers, okay, and arms, okay. But they would lead pipe joints. And they built the big pitch pipe on, okay, 30 inch. And it's terrible, I mean if you have a high-pressure gas pipeline explosion today. And then in World War II tape, they welded the ships. They could build five thousand ships with such people living. I mean, there may have been Rosie the Riveter but she built aircraft because they were made out of aluminum, which is even more difficult, okay. So they welded the ships.

So Tom Schultz's question — your question was, why did we run into all these problems? It was the first really massive use of welding of steel, and they didn't know how to do it. And in fact, since we're talking about that, I can tell you another thing we didn't — you don't know how to do, in general. [Tom retrieves a sample.] This was a little harder to pass around, but this is a weld — I will pass it around. This is a weld, a 17-inch-thick piece of steel. It was part of the forging press they were trying to repair in Pennsylvania some time ago. I didn't count exactly, has somewhere — would be 400, a hundred drunk passes in here. Weld passes laid by stick electrodes. Let's place a little bit, but sure.

Anyway, you look at that — that's how they welded ships in World War II. The stick electrode of the time, four to six pounds an hour, which the welder can put down. And what do they do sometimes? They were tired and they would slug the welds. What about slugging a weld? This movie is — a big thing like this on a cruiser, a battleship, so they take a bunch of electrodes, drop them in the groove, and weld over. Talk about a critical flaw size, okay. And it's not a good thing. I've only seen one slug weld in my life, okay. We tend to know we don't slug weld. That was on Americana things. It was actually here on my wing stop with Boston on it. Intersection on your father's — another one, 28 and 8 next to it — was White Leaders, say. By the way, this guy was from Canada, Nova Scotia, and he had this 40-foot sailboat. He'd gone down to Newport sailing races, keep 12 championship, and he's driving back over to Nova Scotia. He's got this home-built trailer that's got the boat, and here's this — as he's cruising down the highway, here's a big bang, and of course he puts his brakes on, and he sees this boat go by, just ideas, okay. It was his, okay. The trailer broke, and his boat is cruising down with no brakes, the game straight is book. And it turns out, someone in the weld — someone took a bolt between two of the angle irons and stuck it in there and welded over the bottoms, yeah. You wouldn't do that to produce, what, [it].

Student: I'm just going to say it, so let us just see, sorry for my parents there, but like even though welding by hand and causing infections at callus laws, and the boys one's name. So it must feel like this day push the heavy heads of a submarine, and can you tell us how thick it is, because the other side will know how people don't care. Okay, I surprised. This is a very technical, very — pissed. So well, and that's what I — hanging head of which doesn't, she came to frame stand especially for the caps, and it's now breathe feel, so they pre-triangles imagine together and makes them don't perfect angle, and so they don't have guys. And what they do with these pictures, and it goes — they ran a barrel tracks across the stitch really, right. And they put a automated mechanized — your truth, thinking of some welding machine, and they have a geyser strains walk along with it. And so do just relax it, and just wants us back and forth across the swelling, and just it's every time. And at ladies it consistent be down, there's some 100 needs to go into this, because of me much like this. And then of course they flip it upside down, the back out of the back of the weld, just to make sure that our clean surface to weld through. And we're fluids in a bold after have a fan down there, so there's sure going to the accumulation of like inert gases and pass out down there whatnot. And then they do this exact same thing for reverse side. And of course they buff it out, and then kind of rolls down the line, and you can't have a defect bigger than three millimeters in there, yeah. All they are is the beauties for those different welds and stuff, but it is — crank them out, they put those pieces of metal there, I was always something been working on one way or the other. Good wholesome.

So thank you. Did talk about some other submarine stories. Are you familiar with the torpedo tubes? And they have to be very straight, right. And they're pretty long, okay. They're longer than the torpedo, right. And they — after the island of what — the tolerances looks like a millimeter on the belief. And they used to weld them up, of course you get distortion from welding, and then they would machine them with a great big boring machine that would go the length of one of these things. About how long they are, but I'm sure there's probably 40, 50 feet long or something. It was my first student who went to work for Electric Boat, he's now retired — I'm still working — he figured out how to do it so they would not have to straighten them, okay. Basically when they put the welds, it was like you were talking about going around. They actually had something on Homer's, and so then just weld go around. But basically he put some feeler gauges — fee-gauges, because the ones that judge measured distance, Springer distances on the end a couple of feet away — and he could see the angular distortion. And what he would do is he would compensate with the weld. He would stop the continuous weld and go on the other side to pull it back the other way. Or he had to be actually grind out the weld and put another weld in to cause more distortion in that direction. So he monitored in-process the distortion and corrected for it in this cylindrical joint. And all of a sudden, all they had to do was just do a skin pass down the bore as opposed to taking a quarter inch off. For a lot of, how are these materials background, but that was one going to bloom online.

Student: The shipyard, is the all welding is like metal — they're paper and sugar. So if you like, you know, hold it, and warps and bends as you do things to it. So like to show the hole itself will distort events a whole. They have these very healthy plants where they basically spot weld a bolt like a plan, like heading on there, and you can attach the C-plane to it. And the clamping screws onto this tack-welded bolt, and then you can screw it up or down on that bolt. And it has us as a curved portion. So if you imagine like here's a scene of two pieces of metal like this, and have a — this thing bolted here, and press it against this piece of metal, and it goes all the way around the circumference like that. And so you have a full thing like arms right, so the holding orange clamps all the way around the whole circumference of this weld joint. And then you kind of use a air power jack, and then you — it's a, like I'm gonna go ahead of the poor anyway, you're gonna work this whole cylindrical thing within tolerance, people in place, and then you weld it all and it can take all. And so this whole thing is under stress, right. Like the rest of the sub Ernie's life, there's some degree of inherent stress in the metallic structure because you had to line this up, you know, with an exact tolerance, or for the soul wonderful thing both tool and expensive to build, some reason pieces, that's not the entire length of suffering, every modules. Yeah, so he's on the views on the build side of it.

Student: I was on the repair side of it. So when you — we have a lot of corrosion issues with carrier nuclear piping that we're dealing with right now. So like back in the shipyard, when they built the thing, they would jack a pipe, you know, if it didn't line up, so you jack it on it tight, right, choose up to, and weld it. And now groom — she goes into my ears later, and we cut that pipe out and realize, you can't just rebuild it and have your piping line up with no stress. So now you refabricate tired piping systems with a pretty complicated processes that hold it back together because it was easy to just crank it over a few inches and weld it. Yeah, there's a lot of resources goes on a ship. There this is kind of with your partner, but you have your two pieces of your home, and you — you're not a match, so you facing both this guy on how to screw on here. You press this one down and it holds us up, and you're bringing it into the alignment.

If you look at manufacturing tolerances, a typical manufacturing tolerance — it doesn't matter whether you are going semiconductors, you know, something chips, or ships, a typical tolerance is 1 part in 2,000. So if you're a machinist, and if you ever work on a lathe and you're trying to machine something to one inch diameter precisely, you can get about half a — five ten-thousandths of an inch without too much difficulty using a long micrometer and so on. You can machine it to that tolerance, that's a typical tolerance. And it doesn't matter. But if you talk about a ship that's a thousand feet long, that's a one-inch distance. If you're off by an inch, the hulls don't come together, okay. So it turns out shipbuilding is — I used to be able to say shipbuilding — Alan Brown is from the Ocean Engineering Department, he pointed this whole tolerance thing out to me once — Jubilee was the most precise manufacturing that we did in terms of parts per thousand. We're about one part in 20,000 in terms of the tolerances you have to put. And when the sun comes out, or the cloud goes in front of the sun, the whole ship changes shape, solar heating. And you have to weld these things so that there's not a bunch of mismatch.

Student: Yeah, I was the docking officer at the shipyard before I came here, and we dealt with that a lot. Like you build a carrier as it has to be long, and then you got to dock it on wooden blocks, and you actually dock it, you see the thing — like you're saying, the sun comes out, the front end of the ship lifts up because the temperature, just works it's a crazy house. Down in Pascagoula, we actually have some sun shades I've heard, as I'm single, but basically when you're welding out there in the hot sun and stuff, gets hotter down — the gasket, they basically have to control the solar heating, re-see the ice at hotter than el gran.

Okay, any case, so there's a lot of little different things in welding they have to worry about. What more, fun factor in the stove, all it's nothing to hear what I learned it. Without jack clamp it also some chain attached to it because I was — one of weather changes were attached to every single mothers, I became attached or linkage. Why is this chain here? And the idea is that if that's, you have welded, you spot weld and discredit bolt on the side of the pole, which says I'm going to be removed, right. Could have that weld field, that's under pressure because you will line the holes, it'll show you know explode across the whole, like maintenance build a facility, and you could like blow someone tell with that kind of course. So it's not a chain to catch that case, one of those populace. Of course the only reason they do that is because it happened.

Student: So I think this bursary here — I'm sure everyone is working shipyard — you find it that guys get up a lot of effort, don't feel you design. You know, the guys who can pick job instructions for brilliant detailed job, threatens, goes down there, and the guy picking on board, go ahead, use a come-along to pull type against another paper. Yeah, we got stories about that, something that was done that one game. I'm not sure exactly what the — I know I don't have a story of a come-along thing that I did, I wasn't done.

A Boeing story okay about fit-ups. Now there I'm dealing with plate this two or three inches thick. And by the way, at Quonset Point, when they have their welding the whole sections in the vertical — I don't want you rolling, we make you a cylinder because it's a lot of flex down its own way out, that's one of the reasons. But the more important reason: if you make four welds at a time when you're horizontal, make one weld when you're vertical, you can make four welds, that even though each level does slower through the bars on weld, making four-at-a-time is faster to make one fastener. And you also get — you get better residual stresses and less distortion. And so but when they do that, they have to cover the top so the Soviet satellites can't measure the thickness of that ball. Well, I heard that mr. 25 years ago. I thought they're pretty accurate from a hundred miles up, right, be able to measure the thickness, because they want to know that thickness within a quarter of an inch, because any structural engineer can figure out how this sets up to go if they know the thickness of the outer shell.

An important news — Hudson's and Yours Whitney like a year ago, no that was awesome. And they basically had some pictures of some sub Russian submarine, had posts on this blog, but here's the commissioning of the submarine on, attached to this awesome. And you can see that has some bunting and like shark tank over it, it's like a video figured Fox News from a submarine, unfurl a big Kirko this out of it, and senica latifolia tried, but they were like — well, like one flap of the curtain was hopin, you could see like they have a double construction on Russian submarines, as they can see both the holes there. And say to a thickness, and so the brief camera was, this is what we perceive our what the kind of opens I damage our lives would do to their submarines based on the whole thickness and assumed devil operation. Some like that there was something like bubble formation and collapse against the whole for my demonstration computer simulation. If you to just from ping off the Sony, sometimes you think we'll why such as such classified, it turns out you can figure out why.

Let me tell the Boeing story. So Boeing has a spec about fit-ups, okay. Now this has not come along, so this is sort of a Boeing spec. Boeing has a spec that when you're building an aircraft, you're going to rivet the whole to the inside ring stuff in this array, seven cylinders kind of — submarines not quite expect — it's mad up a lighter material. The amount of force you can apply to bring those two in the registry before you make your rivet has to be five pounds or less. That's the general staff. And this is one of the problems Boeing has — they have general specs. They like to write general specs, and sometimes a general spec doesn't fit a particular application, but nonetheless they are. So worried about the residual stresses on the skin of that aircraft, they basically — the structural engineer is sitting in manufacturing — you cannot, you have to form it so that it fits together, you know, within a few thousandths, that you cannot apply more than five pounds of force to bring it into line, okay. So they can things, but they have to — they can't apply 15 pounds. You're applying more than five pounds on your things in the ship here, okay.

So there are different specs for different applications. And then in that case, they're worried about fatigue and the residual stresses around the little rivet holes. In the Navy's case, you just want to make the thing fit together to budget right. And then you come to repair it, you're lucky. I've seen situations where someone cut something and the whole thing goes flying, okay, because of the residual stresses that are locked into the pen. I've never seen — but you've heard of it — I've seen some cases where it would shake it up, they never did. Those are cases where pre-cap. So come-alongs are great, but there's a spring tension that not everybody is going to be worried about them, okay.

So let's actually start talking, after two hours of lecture about welding, about metallurgy in general first. And one of the students last year said — well first time I guess, he said, he asked me the question, why are there so many steels? We're going to get to that. First we have to answer the question is, what is steel? You might know the technical definition of steel: it's an alloy of iron and carbon. And if you go to the metallurgical literature, you'll find a phase diagram for iron-carbon. This was the aluminum-copper phase diagram I showed you a while ago. This is the iron-carbon phase diagram. And if you look down at the bottom, which you can't read, it's a pencil name — John Chipman. John Chipman was the guy who developed this diagram in 1973 or so. John Chipman, Welson's private that our department headquarters is focused on shipping, okay. I tell you, John — he was actually retired when I came as a student, but he developed this diagram. In fact we talked about steels, and they didn't have the same quality steels back in the old days as we have today.

John Chipman came to MIT in the 1930s. He was a physical chemist from Georgia Tech, wonderful gentleman, southern gentleman. And John basically used the principles of physical chemistry to high-temperature melts of steel. So rather than aqueous solutions which is what physical chemists like to study, q5 physical chemistry to 1500 degrees centigrade steel melts. A lot of this was done basement of Building 8 over here. John Chipman worked on the Manhattan Project. He was developing ceramic materials that they could melt uranium and other reactive metals because the uranium and plutonium would react with any oxide. So he's actually working on sulfides. But John Chipman developed the technology to make steel reliable, and there are stories I won't go into. But some of his books or treatises — some of his books or treatises will be found in Chinese libraries enshrined in Plexiglas, you know, because this is the seminal volume that taught the world how to make steel.

And steel is usually carbon steel, by the American [Iron and Steel Institute] standard. It's an alloy of carbon, iron, manganese, sulfur, phosphorus, and they also have okay. Well then, iron and the carbons — I think we can seal this — this is the iron, and iron the high-toughness high-strength material. Carbon is there because carbon can give iron exceptional strength. And in fact the iron-carbon phase diagram here — this is iron going up here, zoom it a little bit more. This is temperature, this is 1500 degrees, this is the vaporization, the vapor pressure line curves as function of the carbon. This is graphite, melting at 50, 300 degrees, or subliming at 50, 300 degrees. Steels are right down here in this corner, cast irons are over here. This is the low-melting just like the aluminum-copper eutectic. Technically it was low-melting. A cast iron has got like three or four percent carbon in the iron, and it melts not at 1500 centigrade but around 1200 centigrade, okay. A lot easier to melt cast iron.

We've been making cast iron for thousands of years, but it wasn't until 1856 that Henry Gus Bernhardt [Henry Bessemer] style melt steel — all the steel that had been — where does steel come from before the 1850s? It either came from meteorites — which meant very valuable, fairly rare, but they take meteorites which are iron-nickel alloys and they beat them down into swords and stuff. Or they would make — they take iron ore and they would reduce it. It's a lot of carbon in a rarefied atmosphere, and they would get carbon monoxide, take the oxygen out of the steel, or carbon form carbon dioxide, and you get sponge iron. Basically making solid-state reduction, and you get this porous spongy I. The Japanese were doing it a thousand years ago, the people in the Basques were doing it 2,000 years ago. India used to make steel, and that's where the steel sword blades of all the hundreds of the Persians, banks deal. But it was very laborious process, you know, but spongy I mean, look like, you ever seen pumice from lava, okay, the fifty percent air, and a guy would forge it, break until he knocked all the air bubbles out together by forging it together. But really it's so then they run a broad context of, you to be able to make steel like that really didn't happen until the application of fossil fuels right.

It would heat something to that — when the fossil fuel, so you can't about steel with fossil fuels what you have to do is you have to praise you with the steel. The Bessemer converter looks something like this. [Tom sketches.] You turn it halfway outside. You have the molten iron-carbon down here. Make sure you put cast iron in here which is three or four percent carbon, you make it into steel, you got to be less than one percent carbon, you got to burn the carbon out. And they knew they could do that, because they made wrought iron for years by blowing oxygen in here. But then you blow the oxygen in as the wrought iron melting temperature increases, you get rid of your carbon, and it solidified on you. And basically the wrought iron they made — they made wrought iron up here and Saugus Iron Works in the 1630s, okay. But it was a very inefficient process of heating, reheating, getting the carbon out by oxidizing the way.

What Bessemer learned is, if you blow the air in such a way that — this way you blow it in this way, such as these exiting gases preheat the incoming gases, you now can get temperatures — hydrocarbons burning in air will get you about 2,000 degrees Fahrenheit, okay. Twelve hundred — twelve hundred centigrade, well not melt low-carbon steel, here's 1200, you're still the solid range, okay. To get that extra three or four hundred degrees, you have to preheat the incoming air. And that's what the Bessemer converter did, by bringing the incoming air in this way and the outgoing air this way. There was a counterflow, very inefficient counterflow, but you basically preheated the air on the end, so this air that got down here to burn with the carbon was preheated already before, about 1200 degrees centigrade. So now I could get 1500 degrees centigrade in the back, just keep it home.

And after that says, see the light, we came up with — Andrew Carnegie came up with the basic open hearth, which is what you'll learn if you read George Lindon's 1960s welding members. You have basic open hearth steel today. Everything's basic oxygen [furnace]. I'll talk about that. But you might as well spend the last little while talking about how to make steel up from. And Carnegie in the 1880s — Andrew Carnegie was the richest man in the world. He was richer than Bill Gates in adjusted dollars. He got rich on steel, and basically the railroads making steel for. Evidently he was worth a hundred million dollars, so that was more than a hundred billion dollars today, okay.

So what they had is they had an open hearth furnace. An open-hearth furnace is nothing more than a big ceramic-lined pot, and basically this thing'd be half the size of a football field. And you can put in a thin layer of cast iron carbon alloy from your blast furnace, and you put a top on this and you blow the air in to burn the carbon off, to take the three or four percent carbon cast iron down to the tenth-of-a-percent carbon steel, and zoom by — the carbon zone or what a co — carbon dioxide. So you get a lot of carbon dioxide. But basic open hearth would have something just as large, actually two of them just as large on either side, which were nothing more than a bunch of ceramic bricks with holes in them. They were stacked in a lattice arrangement, and there'd be one on this side, another on the other side, a stack of ceramic refractory brick. And so to fire this thing up, you would take some natural gas or whatever and you heat up the brick. This thing exercises of the football field, so the whole thing's about half a football field and stacked up several stories tall. You heat up the brick, you then blow the air through here and into the furnace, so it comes in to preheat by brickwork, was only the preheat by brick. And the exit gases would go out through this one end of this one, and you run it for six hours that way. And after six hours, when that was going off, that this was hot, you flip the air and you do that three times. And after one day you tap off three hundred tons of steel, okay. You had to preheat the air. That's how we made steel for the first hundred years.

And then some guys in Europe, in Austria, decided to go back to something similar to the Bessemer converter only. And they would have suggest the end a huge vessel about four or five stories tall, steel that's what was lined with ceramic, okay, so put them up from the steel, cousin won't steal it obviously, melt the steel shell. You have a massive steel maybe three or four feet deep here. You pour the hot cast iron in here, Bolton, caps, I heard it there, and then you bring in a lance, a water-cooled copper, might be about three-quarters of a foot in diameter, and you blow at supersonic velocity liquid oxygen — pure liquid oxygen from there. And that would create a froth of steel. They will fill up the other — 750, 700 vessel just — and in 20 minutes you can do with took 24 hours in a basic open hearth. Kind of place at open hearth, it was surface diffusion. It was air going across the surface. You've got a famu letter that transport that carbon to oxygen one way, the carbon dioxide the other way, slow process, low area of contact, it's a surface reaction. Over here it's like shaving cream. You got lots and surface area, right. And you got — you is pure oxygen, you don't have to add any heat to this, you're burning carbon in there. In 20 minutes, okay, they can take cast iron, 300 hand becomes a — cast iron turning into 300 tons of steel in 40 minutes, okay.

Go ahead, a little particle, oxygen demand steel — if you get down low enough in carbon, but it's only when you get down to less than a tenth of a percent carbon. The carbon will keep the oxygen low until you get very hill apartment. And then if you get very low carbon like this, he gets really expensive to get the last part of carbon out there. And for stainless steels we have to get the last part of carbon out of there. So if you went down, you might see where the glass slab is — the basement of Building 8 before — that's the room where the original research has been done by a guy named Christy in the 1950s. And his doctoral thesis with John Chipman, where he was studying just the carbon monoxide reaction. And so he had a melt of steel and they could bubble oxygen up through it to understand the carbon monoxide reaction, and measure the off-gases and stuff. But he wanted to get to even lower pressures of oxygen, so he started bubbling argon with a little bit of oxygen, as we wanted to have less than one atmosphere of oxygen. So he just diluted with argon, and he was able to do his research from low carbon concentrations.

And then he went to a company called Crucible Steel to work, and they got together with a company called Union Carbide, mothers, and they found — they didn't actually, they couldn't get any big steel company to listen to him. Clay found a theme of this Crucible Steel or charity or somebody, small steel company, that was willing to take a vessel modify it positioner real production vessels and blow our argon and oxygen mixture of argon and oxygen through the bottom of this steel bath. And it's now called argon-oxygen decarburization, AOD. Every — all five million tons of stainless steel with pointy like whatever is in the world made today, it's made by this process. Stainless steel has one-third the price that it would have had in the 1950s before Christy took his doctoral thesis from MIT, my team Klein ministry. AOD was not invented at MIT, but the scientific principles were done by judgeship in prison.

So carbon mix iron very strong, but is it steel right? How does taking as much possible carbon out of steel makes do it? We're going to talk about that. And I don't have to find the next step of minutes. But in fact steel is needed a month a lot of metals. Titanium has the same advantage. It has a different crystal structure at low temperature — body-centered cubic — that turns to high-temperature face-centered cubic. I can demonstrate that later. But because of this it goes through a transformation, a solid-state transformation, 723 degrees centigrade, if it's a ten percent carbon. If it's zero carbon it would be a 910 degree centigrade. That's what this solid Texas, all this line. Now the solid line would solve this line. It turns out what I did quite can show you — the strength of steel is a very strong function of the carbon content. And here's the water — this is so nice it's — will be on stellar hopefully today. This is out of the book called Steels by George Krauss, was one of Morris Cohen's doctoral thesis here, retired from University of Colorado, vines in Lehigh University. But he's Mr. Steel today.

The guy who was Mr. Steel before that was Morris Cohen. Assistant professor here after World War II, when they have all the MD ships cracked and things like that, there were three places that did the study based on this stay-dry report on Show HBU. One was MIT and Horse Scope brittle fracture steels. The other was the Naval Research Laboratory, a guy named Pellini at the Naval Research Laboratory. And we'll talk about Pellini — when he retired from NRL back in the 80s, he came spent the last couple years as a lecturer home here of course 13, which is to end now, and retired on Cape Cod. The other places — place started in 1947 or so by a guy Richard Wek, who was a young engineer in England, pedaling through Cambridge. And he was driving — I remember to tell the story about providing this bicycle into this little town called Havington Denis. He decided this is where she should go, the British wealthiest researchers. So the three places in the world that really studied in the late 1940s through fracture of steel — which is one of the things that caused all these ships, along with poor quality steel.

The poor quality steel: if you have too much oxygen, you don't get the oxygen down. And one of the ways to get the oxygen down is you throw some silicon in or some manganese or someone to get out that last oxygen. So first you take cast iron, which is iron-too-carbon, and then you got to get rid of the carbon by blowing oxygen through, and then you got to get the oxygen down to get the toughest up, okay. There's a whole series of processes, and we'll kind of go through some of those.

But Morris Cohen was — they got here, Krauss is one of the students, and this comes out of this book. This is the carbon content versus the hardness of the steel. And you can see, up to about six-tenths of a percent carbon you have a tremendous change in strength of hardness of the steel, and then ten — law of diminishing returns over there. So what we're going to learn tomorrow is the difference between hardness, hardening, and hardenability. Let me, that — they're very different terms, okay. Hardness is how hard it is, how much it resists indentation. How easy this to the form — hardenability is how deep you can do that, and how we change that. Question?

Student: I have to cross-hatch area shows.

Effective retained austenite. I'll tell you what a great heya — austenite is the part, the FCC structure, that didn't transform. Only George Krauss would get into those pills.

Anyway, one of the most important things about steel and something man's unique and something that I did my like junior year humanities term paper on in my crosshair was the hardening of steel, okay. You can take the same steel that's just cut as it comes off the mill, and this relatively soft, or you can take it and you can heat it up, quench and temper it, and you can make it into something like the file. And I can file down order in this thing with another piece of steel, but this one's been hardened, this one is soft. And the ability to transform shape something when it's soft and turn it into something it's hard is the ability to make a tool. We do the same thing with pottery: we take clay, which is soft, we heat it up — can we turn it into a ceramic which is hard, brittle, the hard, okay. So we do this — this is a fundamental ability of making tools that humans have, that even apes who might do schools, they just take someone hard, they don't know how to transform the material into something is hard.

So I actually wrote my thesis — them not my thesis, my junior year paper on the history department of steel. And there's interesting ways over the years. The Muslims during the Middle Ages thought that the best way to quench the steel — you heat it up, it goes red-hot, and ordinarily water or oil — they liked to take a Nubian slave, a living person, and run the hot, your right up through, push it up. They felt it gave a better edge to the sword. So if you want a short-term profession, you'd give me a Nubian slave, be the quenching medium before Mrs. Steel by the sword. Or something happens — they take the hot steel, you better zark wicked in blood, then in water, catch now because good Brian we find the red myself.