OK, good morning. Before we start here with the next section, so I've been looking at your tests, the quizzes. Again, I want to make sure you all understand, right?

This is a monkey, right? When the monkey takes my tests, yes, there are 10 questions. And he only has to ask true or false, yes?

Although he didn't learn anything, yes, he can still get 5 out of 10 right, just by guessing, yes? So when you take the test, yes, and you have a question that is wrong, yes, you lose a point, OK?

So that means you have student A and you have student B, yes? And student A answers 10 answers, yes? Yes? He gives 10 answers.

And student B gives 7 answers, yes? The student A, yes, has made, has not learned a lesson. He has guessed everything. Yes? And he has made 3 errors, yes?

OK? Excuse me, 3 errors. And he has made 0 errors, yeah? OK? So this person gets 7 points, right? And this point gets 7 points, OK?

OK? But say now, it's probably clear, say he gave 7 answers, 3 errors. Sorry, I missed it. 7 errors, 3, he's got, his points is 4 points, right?

And this is 7 points, OK? So he gives 10 answers. He only gives 7 answers. But he has learned his lesson, right? He knows what the correct answers are, yes? And he doesn't answer the ones he doesn't know, right?

Here, I assume that when he gives answers, he's just guessing, right? So you get minus. This is a common way to evaluate multiple choice questions, right? Because you can always guess. Somebody who doesn't know anything

will just be lucky, yes? And certainly, if you have only 2 possibilities, not 3 or 4, then it's even your chances of getting the right answers. So don't forget that when you take the tests.

Because if you give 10 answers and 6 are wrong, you don't get 4 points. You get 0 points, OK? OK? So I just want to make sure that we all understand this, OK? So the idea is just make sure you go through the material.

You go through the material, and if you didn't learn it, just don't answer. Or you don't remember, don't answer. And I just wanted to know, the first class I asked you to write down your name. Is there somebody called Ahmad Sadimat?

No, it is not taking the class, I guess. All right, I just wanted to know if that person was there. OK, so today, this session, we want to talk about standards.

So because in practice, when people buy and sell steel, they're not involved in research at all. They just want the steel for their application, yes? And so when they describe the steels, they use standards.

Let's have a look at what standards are. They're basically classification methods to identify steel grades. Steel grades are types of steels. And why do we use standards? And why are standards so important?

Because it guarantees quality, product quality, reliability, and interchangeability. You can compare two products, two steel products, with one another. And usually, these standards are coherent, and they're simple, and they should be convenient.

And usually, a steel will have a name, or a symbol, or a number, or letters, or a combination of names, symbols, letters, et cetera. And attached to these grade names

is information about their composition. Perhaps the dimension of the steel will see that there are some grades specified by the dimension of the steel, strangely enough.

Mechanical properties, of course, or other properties. For instance, for electrical steels that are used to make transformers, the magnetic properties will be very important. So we'll go through some development of standards

in material science. And of course, mainly, that is physical metallurgy that's behind these standards. That's the basic of the standards. But a lot of the input comes from professional engineering

societies, for people involved in the use and the trading of steel. So the trade associations play a role. Government regulation agencies play a role. Or also, official standardization institutes, such as, for instance, the ISO, International Standardization

Organization, which is an international organization. So they all have their input. So in general, this is not specific for steel, specific for all the alloys and metals and materials.

So in general, when we look, as steel researchers, at low carbon steels, we look at the phase diagrams. And we say we have steels which have less than 2% of carbon. And some of them will be hypo-eutectoid.

Some of them will be hypo-eutectoid. And the steels are here somewhere. Yes. And of course, cast irons are a different group of ferrous alloys, which we will not talk about. But they're also standardized.

And then we have a whole group of non-ferrous alloys and metals, which also are standardized in similar ways. OK. This first approach is a very interesting approach. But it's just physical metallurgy.

It's not very useful in practice. Because in practice, what happens is somewhere you start by making steel. Yes. You cast that material. You turn it into slabs or blooms or billets. And you go through a plant that

turns it into pipes or plates, sheet material, coated or uncoated. Sections, like I-beams. And then you also have products that are bars, steel rods,

like these rebars, wire products. So you can already see here that there is, both for the producer of steel, this is typically what comes out of a steel plant.

And you can obviously see there is no product here. This will probably may become a car or may become something else. This may become part of a boat, a ship. So the user will be using these things. So they need to specify. They don't want to go to specify

the metallurgy of these things. And the physical metallurgy is pointless, of course. So a product comes out of a plant, a steel. And so this industrial plant is processing, uses raw materials.

In order to control the process, it uses information technology, automation. There is an IT infrastructure that controls the whole flow of materials and what happens to them. So a product is the result of some composition, thermal processing, mechanical properties.

And then it has application properties. And that all leads to a product with great specifications. This particular beam here has specification.

It's a certain steel. It's used in a certain application. It's got a great specification according to a certain standard. Again, we have our plant makes a steel product.

And this steel product, many of us when you're involved in steel research, you have tunnel vision. You are working on texture development of low carbon steels or on texture develop or control of grain growth

in heat resistant steels. That's your thing. But a product has mechanical properties, geometrical properties, microstructural properties, which may be important, and then technical properties. What is a technical property?

Weldability. Magnetic properties, electrical resistance, polarization, resistivity, et cetera. And all these are important when you talk about the product. Because when a car maker buys a piece of steel,

he's not really interested in the grain size or the physical metallurgy of the grain. He just wants a product that will enable him to make a car. So he's not going to specify according to Kim Dong-e's PhD results, I want this steel.

He's going to specify a very specific product. So how should we try to understand this from our point of view? So I like to think about steels as having a steel design

chart. So what the user wants is some kind of performance index. And it can be very varied. But let's say we're interested in mechanical properties,

for instance, will need strength, a certain strength. Now, this property is coming from structure and processing. And you see all the parameters that can play a role. And that performance index is usually

attached to a property. This may not be very clear, but let's have a look at what I mean by giving an example. Cool, right? So the performance is something you find attached to the grade-specific technical

requirements. So in the grade-specific, you'll never find something about perlite transformation kinetics. Yes? The grade-specific technical requirements

are these type of things. They're basically how strong is the material, what's the yield strength tested under these and these conditions. So let's have a look at a typical example. For instance, automotive steel grades for exterior panels

require very high formability. So one of the very important parameters is the Langford parameter, the ratio of the width strain to the thickness strain

measured on the sheet material. That is, what property is this? It's a formability property. That would be in the column of properties. In terms of the structure, what does this mean?

It's related to crystallographic texture and the sharpness of the texture. And in terms of the processing, where are the buttons that you can press to control the crystallographic texture?

Well, they're indicated here. Some of them are related to composition, the vacuum degassing, the alloying of the steel, and some to processing, in particular the cold rolling and the annealing conditions. So these parts are the kind of, these three columns,

as it were, particularly the ones towards the two on your right hand side, are the steel design parameters that we are using. These here, this is where the grade specifications are all

out, is defining how the steels perform in terms of the needs of the user. Well, let's have a look at a steel made by Posco here.

You can see it's a coil. And you see it's made by Guangyang Works. And on the label, it's got information for the customer.

I can see it's Xinhan Precision Industries. So it's an engineering company. And you can see underneath the name of the company, there is JISG3131SPHC.

That defines the product that Xinhan Precision Industries ordered from Posco. So what does this mean?

Because that's the only, that's how they order their steel. We want this. So what does this mean? Well, first of all, you can say that already, first of all, they used a Japanese steel grade

naming method. And they used a certain standard, a certain standard. And the number code of that standard is G3131. And the steel itself is SPHC.

And very often, these letters are short for something else. S means it's a steel. P stands for plain, plain carbon steel. We'll see in a moment what it means. H stands for hot rolled.

And C, it's a commercial quality. Means regular properties. And that's it, basically. And if you want to know exactly what these regular properties are, or this level of carbon,

you have to go to the standard, to this GISG3131 to find out what this is. Just a little diversion here, because we never talk about money when we do research.

But a coil like this, when you see this on the road, you have any idea what it costs? Costs about, in 2003, about $620 per ton. And you can see on the every coil is weighed separately.

You can see it's 11,530 kilos. So this coil costs about a little over $7,000. This is a very basic steel. So you can almost say, this is like the cheapest

steel you can get. Hot rolled, commercial quality. So automotive steels, which will be cold rolled, which may have coatings, can cost $10,000, $12,000, $15,000, depending on.

When you pay for something, you not only pay for the material, you also pay for transportation. So who pays transportation? OK? You buying from me? I have the material. Who's paying for the material coming to your plant?

Always important, yes? Because, of course, if you're transporting from Pohang to Ulsan, it's not very far. But if you're transporting from Pohang to Shanghai, or to an automotive plant somewhere in North America,

Detroit, it's expensive, more expensive than going to Ulsan. So it's always very important. The prices are always quoted. So FOB, yes? So FOB, if you ever confronted with this,

you always have to ask what it means. And you won't sound silly, because it means different things in different countries. Most people, like in Europe and in Asia, when you say free on board means

the seller pays transportation to the point of shipment. And the buyer pays the cost of transport, insurance, unloading, and transport from the arrival port to the final destination. And also, the risks are when does it stop being my coil

and it's your coil? The passing risk occur when the goods pass the ship's rail at shipment. Why do we need to have all these details? Because sometimes you have accidents.

You know, coils sometimes fall off the truck or off the train, or they fall off the crane, yes? So does the client have to pay for this, et cetera? In the US, they use the word FOB origin,

which means that the buyer pays shipping and takes responsibility when the goods leave the seller's premise, yes? It means as soon as it comes out of the gate of Posco, it's the client's problem, yes?

But you also have FOB destination. That means the seller pays everything till the buyer takes possession, yeah? So as I said, FOB can mean very different things. And things are not finished when the product is finished, yes?

They have to get to the client and things like that. OK, anyway, that was just a small detail here that I thought might be of interest to you. So interchangeability, OK? Let's look at the example we have.

So we had the standard, GIST, GIST stands for, by the way, Japan Institute for Standardization. It's very, very widely used in Asia, yes? And it doesn't mean that Korea doesn't have steel standards.

Korea has its own steel standards, but nobody really uses them, yes? In Europe, we had the same thing for many years. Every country had their own standards. British had their standards, Germans, French, Italians, very complicated. Now that there is a European Union, we have single EN steel standards,

which is much more convenient, yes? And the US, of course, and Canada have had, the US I have to say, have had their own standards for many years.

And so these are the main standards that people are using, the GIS, the EN, European Normalization standards. And then you have, in the US, there's much less government influence on standardization. You have more professional societies,

like the Society for Automotive Engineers has standards. The American Institute for Iron and Steel, and ASTM, Mechanical Engineering Society, American Society of Mechanical Engineering, et cetera.

We'll talk about this in a moment. And because America is such a big market for any product, basically any material, they also have a big international impact, yes? So let's just, and that's why I'm concentrating on these.

It doesn't mean that the standards, Korean national standards are not good. They're perfectly good. But chances are you will probably not use them very much, yes? OK, so let's have a look at this standard here, 3131 SPHC.

So there is a, we can find in the US, an equivalent steel, yes? And ASTM, A36, or also well known as A283. Don't worry about the numbers here, right?

Hopefully be able to give you some insight about the numbers. And then the European normalization for this grade would be S275, yes?

OK, so this particular steel, types of steel here that are regulated according to just 3131, that's not, doesn't control, doesn't describe only one steel. It gives data on the properties of other steels.

So SPCH will be commercial. That's really basic hot rolled grade. But you can also have hot rolled grades that are easily press formed.

So we call them drawing qualities, yes? And instead of a C, there is a D, yes? Or you can have deep drawing, hot rolled qualities. And then you have an E here, for the E

of extra deep drawing, OK? And so you can see here, for instance, that these steels are very comparable strengths. However, the requirements in terms of compositions are tighter, yes?

OK, let's have a look at another product here. It's also made in Korea by a subsidiary of POSCO called POSCO Special Steels, yes?

And here we can see a similar type of label on the product, yes? Not all the products that come out of a steel plant are sheet or wire. Some of them are just billets that will be processed by clients, yes?

So this billet has already a sticker, yes? And it says, again, GIS, yes? You can see that POSCO does not use Korean standards at all. As far as I can't even see it, yeah?

So again, GIS, so it gives you the standard 4105. That is a Japanese industry standard code number. That's basically the number of a document where this information is, right?

And it says SCM440, OK? So what does this mean in this case? Again, it's GIS, yes? The S stands for steel. The C stands for chrome.

And the M stands for molybdenum, OK? So this is an entirely different steel, OK? You wouldn't be able to know this if there wasn't this curve, yes? I wouldn't be able to tell, just from looking at the steel coil, that it was a very cheap, hot rolled material

with commercial grade. This is a much more advanced material, yes? Much more highly alloyed, yes? Obviously, it contains chrome and moly. So as I say here, it's a continuously cast billet.

And it can be used to make wire rod. And this wire rod itself can then be turned into ball bearings, nuts, bolts, wires, tire cords, springs, you name it.

All right. So again, let's have a look at, first of all, equivalency. So the SCM 440 Japanese have this symbol for it. In the US, there are equivalent grades, yes?

And the American Iron and Steel Institute and the Society of Automotive Engineers have an equivalent grade, which is called 4140, yes? Every standardization group has different ways

of doing things, OK? This particular AISI and SAE, they only use numbers, right? So but if somebody tells you what these numbers mean, you can certainly see that number and you know what it is.

And we'll see that in a moment. The European normalization is a little bit nicer to everybody because there's no mystery about the name, OK? So it says 42CRMO4, OK?

So you can obviously see you don't have to think what the C could mean or what the M could mean, right? You know it's chrome and moly, yeah? We'll see that in particular for the European normalization scheme. The 42 is related to the mass percent of carbon.

And the 4 here is related to the chrome content times 4. So 4 means there's actually 1% of chrome in it. So that's the only problem with the European way is you need to know the conversion

factor for this number, which usually it's 4 unless it's different. So again, right, and there are molybdenum additions. We can see this because it's in the reading. In this case here, I also know

it's a chrome moly because it starts with a 40. And I know that it starts with a 4. It's a chrome moly steel. But that's because I know this and you don't know it. But after today, you will know it, OK?

So this steel, again, is a medium carbon steel. It's alloyed with chrome and moly. And obviously, we know that chrome and moly increase the hardenability of your steel, yes? So we'll be able to make things that are high strength. And one application is, for instance, bolts, yes?

And that is done by a process of different process steps, ferrodizing and annealing, cold heading, cold heading being forming, and then heat treatment to get the final property. And the bolt and the nut are not the same metal, OK?

So this is a typical composition. The grades specifications, so if you buy the grade specification, yes, it doesn't give you a composition. It gives you a range. Let me get a pen here.

It gives you a range for the carbon content, yes? A range for the manganese content. It may specify a certain amount of silicon. Usually, this is a maximum, yes, that is specified, a maximum. And it gives you a range for chrome and for moly.

And if you take, for instance, this particular example, the composition is here. And you see that the steel maker is free to choose within this range what he provides, yes?

But lo and behold that he sells a steel under this name with this much chrome, yes, and there is a problem with the product. This will be a major problem because this

is the specification. And the specification with regards to the composition is very strict, yes? So again, typical applications for this is bolts, as I said, but gears, shafts, couplings,

spindles, et cetera, in general, in the machinery applications. The carbon content, this is important here, is relatively high. So that means the welding may be difficult, yes?

So in order to ensure good weld quality, you will need to preheat the material and stress relieve it after the welding. So what's very interesting is that a material does not

necessarily go from the steel plant to one client and then becomes a product. There may be different steps, yes? And the material can change hands a couple of times. And an example is, for instance, with making bolts,

we call this, the steels that are used to make bolts, we call them cold heading qualities. Cold heading that describes the process, the mechanical deformations we use to make bolts.

Bolts, nails, screws, we call them fasteners. You use them to fasten things to one another, yes? And the steel qualities, we call them cold heading qualities. So they usually, when you make bolts,

you start from wire rod, yes? And the wire rod may originally have been billets, the billets that I showed you, right? So these wire rods, these billets don't necessarily stay in the steel company. They may be sold straight from the steel company to a wire rod manufacturer.

So this wire rod manufacturers, then the first thing they do, they soften the material, yes? And they may draw it, yes, to a certain diameter. And then they usually spheroidize it before they do the cold forming

to get very low strengths and so that they can achieve easy forming of the bolt, yes? And eventually, once they have the bolt, they will do a quench to martensite, and then a tempering, yeah?

So this particular step here of spheroidizing, yes, where you reduce, you can see here the strength is originally very high, very hard material, yes? After the spheroidizing, it's reduced by more than half, And that is because we, this is an example here

of spheroidizing, we turn the perlite here, yes, into ferrite plus spheroidized cementite. And that makes the materials very soft, OK? So this process takes a long time, the spheroidizing.

This is an example here. For instance, if you want to spheroidize iron carbon, it takes you 100 hours, so a few days to spheroidize this. If the material is alloyed with nickel or moly or chrome,

it takes even longer, OK? This spheroidizing process is very important. Again, the nut here is not made with the same type of steel, but it's made with medium carbon steel that doesn't contain any chrome or moly, all right?

Not only, so this steel here that is used to make the bolt, yes, we need to, yeah, we need not only to have

spheroidizing information, we also need to have the quench and tempering information. And by the way, so the process of making wire, yes, and spheroidizing may happen at one specific client,

and then the process of making fasteners themselves usually happens by specialized firms who actually make the bolts. And so as I said, there may be two or more guys, companies in between, the steel maker and the bolt maker,

bolt manufacturer. So let's go on here. So for the last step, again, you will need to, the person who makes the bolts will need to know at what temperature

he could forge this, at what temperature he can anneal the material, normalize it. And really important is the hardening and the tempering. So how, at what temperature does he have to anneal it? What is the minimum cooling rate

he has to achieve to make the structure martensitic? And what is the tempering conditions that he has to use? This information is usually not standardized, not provided in the standards usually, but it's

provided by the steel manufacturer to the companies that buy the steel. Another example here, this time we look at a material that is turned into a geared wheel

here with carburized, that means surface hardened gear

wheels. So this is a AISI 5120, which is the same as the SCR 422. Now you know that if it starts with an S, it's just standard.

And S stands for steel, and CR stands for chrome. So it's a chromium steel. This is the equivalency. And so usually these billets, this is a cast billet, will be forged and machined to get the gear wheel.

It will be heated and at the same time carburized. Carburized means you diffuse carbon in the surface layer, so you get resistance against abrasion.

And then you quench and temper the wheel, and then you get the gear wheel, and you get a product. So important here is compositions. You can see here carbon content is 0.2,

but really the key addition here is the chromium. And again, it's to make the steel hardenable. Now you've already seen here when I discussed steel grades according to specifications,

I was talking about the composition. But there are grades where composition is not the only thing, and it can even be dimensions. So for instance, you have specifications for rails.

Now you're probably only familiar with rails that are used for trains, but you used rails for many other applications.

One of the applications is cranes. Anything that is heavy can be moved around on steel rails. And very often, the grades for these rails

are described, again, in special specification. In the case of rails, it's the UIC. UIC is International Professional Organization that deals with rails and rail infrastructure.

And UIC stands for, it's a French word, it's International Railroad Association. Union International de Chemin de Fer. It's in French.

And so a very common type of rail is UIC 60. And you would think that that is a steel grade. Actually, it's the shape of the rail. And in particular, the 60 refers to the mass

of the rail per meter. So if you have the section, these sizes, and the shape of the rail is fully defined by the grade specifications. And so it should weight about 60 kilograms per meter.

So that's what we call it, UIC 60. And the specification is UIC 860. There are, of course, composition and strength requirements for the steels that you make rails from.

And these are, for instance, in Europe covered by EN 13674. And these are interesting. You can instantly recognize them because they start with an R, R for rail, yes? And the number, very conveniently here,

doesn't refer to strength, or tensile strength, or yield strength, but refers to hardness according to the Brinell scale. If you ever wondered who uses the Brinell scale, well, now you know, railroad people use Brinell scale.

And why would they use hardness? Well, that's because that's the most important property of rails, is the rolling on the rails creates a lot of frictional damage.

So you need to have high hardness. So the strength is, of course, important. And the yield strength is important. But what's really important in practice is the hardness. And by the way, typical tensile strengths of rails are 1,300 megapascal.

So it's really hard material, yes? Depending on the applications, other specifications. So crane rails are different. So not the same specifications. But I like the example of the rail steels because it shows you that because of the application,

the grade specifications and what's important in the grade can vary widely. So let's now go into, leave the examples,

and go into our standards. So let's look at what I think you should know about the GIST standards. Well, we have, first of all, the GIST standards for materials, for steels, the specification, the grades,

they all start with S. Yes? Because these are the steels. GIST is a normalization institute that does not only normalization for steel. They normalize everything else. Copper alloys, aluminum alloys, magnesium alloys, plastics,

et cetera. So the grade specification for steels is with the S. So you recognize them this way. For the alloy steels, you can also instantly recognize them. Chrome, chrome moly, nickel chrome, nickel chrome moly.

OK? We can, by comparison of the grades, define equivalents. For instance, these would be the American Iron and Steel Institute equivalents for these steels. They have carbon steels, for instance,

structural steels, which you will see. You should also know structural steel here. Excuse me. And then C for constructional. Free-cutting steels, spring steels,

SUP7, bearing steel, SUJ2. And there, the lettering is a little bit not logical. But anyway, an important thing that I've marked in red here are the two last digits.

And you see that the two last digits of the GIS and the AIS coincide very often. Here, the 20 coincides with here. And that is the carbon content times 100.

So this is 0.3 carbon. This would be 0.2 carbon, 0.6 carbon. And this is 1% of carbon.

Let's look now at the EU standards. So the EU standards have had the advantage that many countries collaborated in it. And so the system is a little bit, I think the information in the name

is a little bit more informative. But there again, you have to remember some of the details. So this is the name of the important standard, EN 127-1. It has two approaches to classifying steels.

So the first classification is related to properties. And the other classification scheme emphasizes composition. So the first classification is a combination

of a letter code related to application and a number code related to properties. So the mechanical properties we talk about are usually the yield strength in mega Pascal. And the application codes are based

on the first letter of the application. For instance, S is structural steel. D for drawing steel. High strength steel is H. Presser vessel steel is P. T is for tin plate or packaging steels. And M is for electrical steels with magnetic properties.

And then the second way of classifying the steel grade is based on the chemical composition. And here we have, and then it becomes a little bit difficult, we have subgroups. And all the standards go into, it

doesn't matter, GIS or AISI or EN, they all have this approach. So first, there is a subgroup one where we basically have unalloyed steels, which are usually referred to as commercial grades, unalloyed steels. And in the European norms, it's

C, unalloyed steels with manganese contents less than 1% in weight. The second is unalloyed with manganese content up to 1% and any other alloying element less than 5%.

And usually, there's nothing in front of that. There's no symbol for these grades. Then we have X. When you see X in front of a European steel denomination, it always means it's alloyed. And the alloying level is 5%.

So there is, as soon as you see X, it means the steel contains more than 5% of an alloying element. And then we have special, most standardizations have special grades for high speed steel

because they're alloyed with high levels of very strong carbide formers, such as tungsten, moly, and vanadium, and also alloyed with cobalt. So let's make it simple. Let's just give some example here.

So a construction company can buy a steel called S355. So what does this mean? If this is this, yes, so the first symbol is a letter.

Then we have three numbers, number, number, number. And then there may be some symbols here, which are related to requirement symbols, which is a number and a letter, and extra symbols, which

are additional requirements, for instance, related to the processing, thermal treatments, and coatings. OK, so let's have an example here. S355 means S stands for structural steel.

It has the S of structural steel. The 355 means a minimum of 355 megapascal of yield strength. So this is a constructional steel that will be used to build something with it, yes?

Right, so I can stop there. But I can also order a steel which has symbols JR behind it. That means there is an additional requirement in terms of toughness, yes, toughness.

So for instance, if it's a shipbuilding grade, I'm going to use it to build part of a platform for the oil industry, yes? I can require some minimum toughness requirements.

And they're defined here as JR. We'll see in a moment what this means. And for instance, we know that when you want high toughness, you want fine grains, yes? When you purchase the steel, you can require

that it be normalized, that it went through a final heat treatment where they austenitized the material and cooled it back down. The two times you do the transformation gives me grain refinement, right? So you add a requirement N. So this

is what you order, for instance, an S355JRN, OK? There are many symbols, OK? The one we just described here for this additional treatment

is normalized, this here, right? But you can ask for, for instance, the material can be, you can request it to be as rolled. You don't want it material annealed. The client will do it himself, yes? Or you want to use it in the cold deformed state,

so as rolled, OK? OK, et cetera. So there are plenty of possibilities here, yeah? Or you want it Q and T, plus Q and T, quench and temper. That's very often used, yes? All right.

About this toughness, I just want for those who are not familiar with this, this is a toughness tester. You put your sample here, looks like this. And you hit it with this big hammer that is, so this big hammer is sitting here.

This hammer slams into the sample here. And it breaks, or it doesn't break the sample, yes? When you do this with this dial gauge here, you can measure the energy that is absorbed during the hit, yes? OK, and that is the way we use to define toughness.

So what you often get with ferritic steels is that when you measure the absorbed energy, yes, on this dial here, you find that there's usually a temperature where there is a huge drop in the toughness,

yes? And these temperatures are usually low, but these are still temperatures that do occur in nature. So we're very concerned about this,

and that's why certain constructional steels have this requirement for a minimum toughness, for instance, a minimum toughness of 27 joules at a certain temperature, yes? OK, and that is this requirement that we

We just saw, remember we had S355 was our steel, yes, 355JR, yeah, so here is JR. It means that the impact energy, yes, minimum impact energy that the steel will have at

20 degrees C will be 27 joules, yes, okay, but I can also say, I could have also asked for an S355K2, yes, that means that here I want a minimum of 40 joules at minus 20,

okay, so this is a much harder toughness requirement, okay, and you can specify a steel according

to this, yes, okay. Another example, let's see, of this EU standard, say we have a steel called DCO3ZE, okay,

what does this mean? Well, again, it's our EU standard, so D is an application, yes, D stands for cold drawing, sorry, drawing steel, the application properties, again, three numbers, excuse me, first a letter

and then numbers, then requirement symbols, which can be alphanumeric, yes, alphanumeric means it can be a letter, combination of letters and numbers, and then extra symbols require, which are also related to what you need or what you want in terms of processing,

thermal treatments or coatings, okay, so this is the example, DCO3, excuse me, C stands for gold rolled, and O3 in the case of drawing does not refer to strength but refers to

the level of formability, O1 to O6, O1 is just commercial grades, steel formability and O6 is for very formable interstitial free grades, instead of this C, you can have

a D if it's hot rolled and X if it's not specified, yes, in this case, I don't have a requirement symbol but I have a ZE, this means that ZE stands for a galvanized coating

and the E stands for electro galvanized, galvanized means zinc coating of course, the coating has to be applied in an electro galvanized manner, by electro galvanization, not by hot dipping, but for instance, if the steel had to be suitable for enameling, to apply

an enamel layer, for instance, there would be an EK here, suitable for enameling, okay, great, so there's a couple of examples where you see one way in which steel can

be specified, yes, with the requirements clearly in the name, again, that's not the

requirements, you have to get the grade booklet, as it were, where there will be all the details about the specific grades, but so in these EU standards, we can also, there is also a method, yes, that's used to describe the composition and again, as I told you,

we have four different type of steels, yes, so we have the unalloyed steels, less than 1% of manganese, unalloyed steels with manganese up to 1% and all the other elements

less than 5%, alloyed steels we call those that are one element at least has 5% in weight and then we have a special section for the high speed steels, it's always best to look at an example, so for instance, C35E for instance, C we know refers to the fact

that it's unalloyed with less than 1% of manganese, yes, and these two numerical numbers here,

that is the carbon content times 100, so the carbon content is 0.35, yes, so I know the real physical metallurgist will have mole percent or mole fraction or atomic percent, in technology it's always mass percent and very often people say weight percent, although

weight percent is not really correct, it's mass percent, but anyway, so weight percent and this little e here, yes, is related to a requirement that you have very low sulfur, okay, another example here, for the second one here is 13, yes, and the second one

this you'll see very often, so the name of the grade will be 13 CRMN, 4, 5, okay, so

the first two digits are carbon contents times 100, CR, excuse me, chrome and manganese are

the main alloying elements, yes, and the 4 and the 5 are related to the amount of chrome and manganese, so 4 is not 4% of chrome, but it's 4 divided by 4, so it's 1% of chrome,

and 5, it's not 5% of manganese, it's 5 divided by 4, so recently I was at POSCO and there is a grade for instance nowadays, it's called 22NMB5, yes, this doesn't

mean that it has 5 ppm of boron in it, it has nothing to do with boron, yes, so first of all, there is no symbol in front, no X or no C, so you know it's alloyed, but everything is less than 5% and the manganese content will be given by the grade symbol

here, so 22 means 0.22 carbon, manganese and boron are the most important alloying

elements, yes, and the 5 is always, the first number is always for the first element, so the 5 can never be for the boron, okay, it's always for the first element, and

so I have to divide by 4, so the composition is 1.25% of manganese, alright, alright, so yes, why is this crazy system of dividing by 4, well it's, because then you don't

have to write points, and it makes it easier, you don't have to worry about, you know,

when you type things, you don't have to write 0.22, because maybe somebody makes an error and writes 2.2 or 0.022, so there is no risk of making errors when

you're copying or writing something, because there are no decimal points in this way, so that's the reason behind this, okay, and of course the result is that it makes things confusing, because if you don't remember that you have to divide, you know you have to divide by something, but you don't know how much, but anyway, it's 4, that's the

one I remember, yes, but it's 4 for chrome, cobalt, manganese, for the main alloying elements, yes, it's 1, it's divided by 10 for molybdenum, aluminum, etc, yes, divided by 100 for cerium, nitrogen, phosphorescent, and divided by 1000 for boron, usually the

only one you have to remember is 4 for, you know, the main alloying elements, yeah, and if you don't remember the other ones, just make sure you always have these lecture notes close by. Now, when the alloying concentration is higher than 5, yes, you stop doing this,

yes, okay, and now your grade will for instance be X, let's say G, X, 2, chrome,

nickel, moly, 19, 11, 2, okay, so this would be also a great specification, so what does

it mean here, yes, this means that it's a casting, it's a cast, okay, so this I will, not so important here, but so it's X, 2, chrome, nickel, molybdenum, 1911, yeah,

so when you have an X in front of the name, you know, all the numbers are the right numbers, so carbon is 0.02, yes, 0.02, the chrome I don't have to divide by 4,

it's 19% of chrome, the 11, I don't have to divide by 4, it's 11%, and the 2, I don't have to divide by 10, it's 2 molybdenum, and of course, this is a stainless steel, yes, it's a stainless steel, and all the stainless steels always start with an

X, because they have these high levels of alloying, all right, HS for high speed steels, yes, usually come like this, HS, and then 4 numbers, like in this case 2, 9, 1, 8,

okay, and so that you always know it's a high speed steel, and the 2, 9, 1, and 8, they are in sequence, tungsten, moly, vanadium, and cobalt, yes, so you really have to know

that it's, I don't even remember, tungsten, moly, vanadium, and cobalt in sequence, so you basically know it's a high speed steel, yes, high speed steel meaning for machining purposes, yeah, and these are the compositions of these, these are the

carbide forming elements, and of the cobalt, all right, so this is an example here, right, of course, what we're discussing this lecture, and I guess part of the lecture

next Thursday morning, is just the tip of the iceberg, right, there's a lot of applications, and all these applications have specific grade denominations, but let's

have a look, for instance, at tool steels, tool steels, these are steels that, you know, for forming tools, like when you make a die, if you look at the big forming presses in the hall here, the dies are not just steel, right, they're not the same

steel you make cars with, these are special steels, yes, die steels, tool steels, we call them tool steels, so for instance, if you do cold work steels, you have forming tools, you have knives, if you do plastics, it's different from steels, if you do cold forming,

it's different from hot forming, etc, but let's have a look, you can still use this simple method to describe the composition, for instance, this says X38 chrome moly 16, okay, carbon content 0.38, chrome and moly are the main alloying elements, there's only

one number, so I know it's for chrome, yes, and because there is an X, I should not divide by 4, so it's 16% of chrome, yes, same with here, this is 0.5 carbon, 5 chrome,

1 moly, and I don't know about the vanadium, right, same here, high speed steel, oh, this

would be an H here, so the sequence, yes, so it's 6 for the tungsten, then 5 for the

moly, and I guess 2 for the vanadium, and there is no cobalt, so there is no number, no fourth number for the cobalt, okay, so usually you can get a lot of information on this, using the European norms, okay, so at this stage, I've come to the AISI,

and SAE standards are also very, very widely used, so I'll stop here, and we'll pick

up this problem of standardization on Thursday.