Modern Steel Products (2014) - Major Applications: lecture 24

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Formal Metadata

Title
Modern Steel Products (2014) - Major Applications: lecture 24
Title of Series
Part Number
24 (2014)
Number of Parts
31
Author
Cooman, Bruno C. de
License
CC Attribution 3.0 Unported:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal purpose as long as the work is attributed to the author in the manner specified by the author or licensor.
Identifiers
Publisher
University of Cambridge
Release Date
2014
Language
English

Content Metadata

Subject Area
Abstract
Professor de Cooman describes some of the major applications of steel in the context of the production technologies and metallurgy of the alloys. This is a part of a course of lectures given at the Graduate Institute of Ferrous Technology, POSTECH, Republic of Korea.
Keywords
The Graduate Institute of Ferrous Technology (GIFT)
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Tin can Buckelschweißen Belt (mechanical) Computer animation Cartridge (firearms) Spring (device) Spare part Spring (device) Steel Fighter aircraft Sommerreifen Cord (unit)
Hot working Coating Ballpoint pen Machine Connecting rod Casting defect Surfboard SKF GmbH Sizing Timken Company Computer animation Screw Automobile Cartridge (firearms) Drive shaft Etrich Taube Spring (device) Plane (tool) Spaceport Bus Wire Steel Material Coin
Typesetting Ballpoint pen Monorail Bridge (nautical) Cord (unit) Computer animation Automobile Austin Motor Company Cartridge (firearms) Mining Wire Steel Ship of the line
Computer animation Ballpoint pen Alcohol proof Estudio Lamela Ship of the line Printing Weapon Surfboard
we 2 so what such as some of these
products that represent the the highest-ranked steals that you can possibly a purchase today for applications and so what France all the time the players in have area and use these these products fighters as the beads here yes that makes sure the euro new tire is itself airtight yes and then and then here did the and part of the construction of the tire you have these belts of a a tire cord look at that very important is that in all cases strength but would equally important as the cleanliness of the steel cleanliness of the steel yes friendliness very important because the product has a small section and of it in the people applications such as the springs I you have suspension springs for instance and also the valve springs yes you need a very high fatigue resistance and that also requires at very high level of steel cleanliness in addition to strike these were typical why
products and then the bar products are shown here that's not within the main applications or shafts very big application are these crankshafts for automotive them but heavy Springs Kaba Aye skiers is also very big application area for 4 yes I and of course in the many cases forums like if you were to have these the shafts machine ability there is an additional requirements fatigue is important In addition to the strength of this can the fatigue fracture is there very big issue In NBA products that I for instance uses of broken a crank shaft and another shaft here that broke through 1 of torsional fatigue yes and it's a big issue of and as you know very often may notice from you courses in the fatigue and if you were interested in fatigue in general there is there is of course a professor of drugs from the teachers on the fatigue of internal cleanliness of the Steelers essential sold because that's usually where the fatigue cracks are in so have a look that these products these a general probably covers most of the the products of 4 why you're With all the most the important ones are this will hold a cool-headed quality products tired color products wire steel products the bearings steals and the free still has this from the work represents the largest of Tulloch and when we talk about goaltending quality we also talk about the products of so-called fasteners and and and what our fasteners bolts rivets screws you have of course when you need to make wire for nails fences that material is softer yes and so you have soft wire rod that use in this case and what you see but in terms of the composition I do want to point this out to you that the compositions are very much composition where we get the strength from the car yes get the strength from carbon and From what we do to them like rastructure when you have high carbon you know that if you are if you have a equilibrium situational have felt for this kind of carbon levels you have right and pro-life yes so you can do something to increase its strength by refining the mike awestruck too great smaller grain sizes and refining the Inter Lamela spacing in the perlite you can also turn this the steel into markets that's not sight you can tell With what grades you typically would do this yes where do you see the car the chrome content for instance from content on the higher end instance you see here chrome contents Close to 1 per cent In the case of spring steel bearing steel take little bearing steals that levels of chromium points to the fact that we are making markets I would not using the a political microscope and ended the chromium that's added in this particular case is on To make the steel pardonable interviewed easily get Arkansas now it's also
very important to realize that the product that's created the steel plant doesn't really have the properties and Mike rastructure Of the for instance the bearing steel order cold heading the quality of faster so their are usually many steps between the production of wine around and for instance a bold for a bearing or steel port that you will be able to use it 8 in a in the in tight against so let's have a look for instance we we were going through to all of them will we which will let you see if few things and which would would basically see here is that there can be multiple steps In the process the steel company well world bring this wire to a company that well additional thermal treatments suggests sterilizing before it actually gets to the company that will make bowls or barracks and given the state of the India the steel its final application for instance from Posco may be making guests the steel wire here but the Bulls are not made by the difference is made by a the company very famous company From Sweden SKF vary In future for Timken 1 of these companies a specialized they don't make steel than it may not make steeled themselves and and and thereby at the basically by these
the steals from steelmaker began what's really important here knows is that and these the wires steals belonged to the strongest types of steals you can get steel cord in the car tires easily reached 2 3 thousand mega Pascal bridge the bridge wire it's theirs is only to 2 the the Pascal yes the Standard Nos 2 few words again
about the the mike rastructure here so when you make perlite I love you you can make a fully because we'll see we make fully paralytic Mike rastructure yes at compositions exactly the paralytic composition so what would do I want to stay here if I if you look at the again still very simple most of the time as you only need to look at the Baron rich corner of the phase diagram so obviously when you have foreigners in this case 4 . 8 per cent of carbon you expect to see know well it's not strange that you could it but verite seamen diet laments yes madam but it turns out that if I have a composition here or have composition there I can also get but fully politics Michael structure In that sense demonstrated what hunting you get fully prolific if you're not exactly and political microscope I want to understand this you have to understand why which makes perlite growth so when the ball let's let's see what makes polite grow and ask ourselves why does purloined pro In the I have here far-right and a half years this far-right has very very little carbon common very very small and he here the carbon is about pretty high close to 7 wafers but and we know that in order to grow this is gamma in order for this interface to go from here to here will be Seaman tied to growth yes I basically need to get carbon to go from here to there makes sense right they have to get rid of it but then how would that work because there's no carbon here and is not a carbon there with carbon go where there's lots of carbon already but obviously the reason because the carbon goes from this region of Austinite to this region of Austin From this area into to this area now what is the carbon content here and the carbon content here that is the question has not obviously the carbon content I just told you to comment ,comma with a carbon companies fairer than what the carbon content is the segment of best but that's not what makes the carbon moved from here to here what makes the carbon move from here to here is the carbon content at the far-right Austinite boundary and hear the carbon content at the tied also denied number so sigh I am I would like to know what what these what these concentrations are that's what are these concentrations if I look at this phase diagram if I look at this phase diagram hormonal problems say I'm doing deeper like transformation at this temperature this is the temperature at which I do the transformation Austinite too far-right plus parallel what is the carbon content at the interface of a government of a and B Simone tight there and so I look at this summer's wall on my supposed to know you know that I can't get the information right the reason is of course is this phase diagram yes tells you what is here at equilibrium has but we don't have equilibrium when you do the transformation at this temperature you still have Austin during the transformation but there and in order to know what did concentrations are these 2 concentration I need to extend these lines I need to do no where these lines would be if there was no the prolific transformation basically if you will see that it would be a basic need to extend and I can do this computationally from what I need to extend the 83 lines and I need to extend the NEC and and if you do this us what what is this line here in this line here compositions here correspond to Austin seem entirely concentrations and compositions on this line correspond to Austin 2 McKnight also corresponds to far-right Austinite yes and of course that continues here this is the carbon content at the boundary between Austinite and fair during the transformation and this is the carbon content at Siemens tied Austinite battery during the transformation and now you can see that yes it makes sense the carbon content at this interface this is higher then at this interface and so the carbon will move from here to there and it will be controlled later diffusion coefficient of carbon in Austin it's the controlling parameter it also means yes that I can I can make perlite when this condition is achieved when the concentration here yes when see Peter Gammons is smaller than city of them and so that means I can have I can form perlite inside this triangle and I do not need to have exactly the perlite composition by Canada slightly less slightly more and you can see it's an it's not necessary to have . 8 per cent of carbon you can make the perlite if you have . 6 % occurred and it will be fully paralytic the or I can go to . 9 per cent or higher analysts still be fully primitive and because perlite can grow viii but you can also see of course that things will change depending on the temperature at which I work so so that's
important the so I have controlling a controlled by the carbon content as and so on and in the process of creating this is just the start of this process here is Gamma Gamma grain boundaries you start forming Little variety seem nuclei so it's a nuclear nation and growth process so if you look at the kind that takes of the transformation I see that very close to 81 was I don't get much better at low temperature also don't get much in terms of transformation that's because my diffuse the parliament facility becomes lower but there is a maximum rate of transformation and so that's important and we'll see this Back indeed when we look at the processing of the steals has between 600 550 and 600 we get the very fastest growth rate the takes 1 2nd for the perlite transformation to start so very fast and that's where we also get very fine per line look OK what is fine purloined that's where you have is small intra Lamela spacing them small Inter Lamela spacing means that you have a loss of interfaces has also interfaces so any time you have an interface that means you have more energy into official energy so small Inter Lamela spacings are unstable so if we hit you keep this up With easily it can easily cost In fact from a purely thermodynamic point of view even the perlite is unstable again because of all this into facial energy and if you keep perlite long enough at between 6 and 7 and degrees C it will Sparrow dies the the perlite will turn the 2 media seem entitled turned into little balls and that will minimize the Inter facial energy however From an application point of view this Is this what we walked that's because that's where we have the best
properties and that's the reason why so as we decreases the temperature at which we do the good that day the transformation of what we see is that so again in the region of 600 2 515 you see here that the growth rate of the growth rate of the perlite very very high enter and the corresponding Inter Lamela spacing is also very small so you can get into a lamellar spacings which are between 0 . 1 per
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