Modern Steel Products (2014) - Rolling of Steel: lecture 11

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Modern Steel Products (2014) - Rolling of Steel: lecture 11
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11 (2014)
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Professor de Cooman builds on the previous lecture in the sequence, about the hot and cold rolling of steel. 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)
Automatic watch Kickstand Clothing sizes Saw Rolling (metalworking) Surface mining Spant Rolling (metalworking) Remotely operated underwater vehicle Material Mail (armour) Material Sheet metal
Friction Rolling-element bearing Rope Gentleman Rolling (metalworking) Commodore MAX Machine Surface mining Guard rail Ship of the line Mail (armour) Material Vertical stabilizer Kickstand Printing Gas compressor Seeschiff Ammunition Gentleman Rolling (metalworking) Surface mining Work hardening Lubrication Remotely operated underwater vehicle Material Ship of the line Friction
Control engineering Waffenleitsystem Airbus A300 Hydraulische Maschine Automatic watch Screw thread Arbeitszylinder Brickyard Mechanical watch Rolling (metalworking) Spare part Mail (armour) Sheet metal Van Wägezelle Hydraulische Maschine Strömungswandler Gas compressor Spant Ammunition Faltenbildung Rolling (metalworking) Cartridge (firearms) Arbeitszylinder Automatic watch Screw Gate valve Caliber Model building Disc brake Friction
Schneckengetriebe Nut (hardware) Kickstand Mechanic Automatic watch Reference work Piston Thrust Arbeitszylinder Gear Transmission (mechanics) Mechanical watch Mountain Screw Commodore MAX Machine Spare part Engine Mail (armour) Cylinder block Sheet metal Truck Wägezelle Hydraulische Maschine Clock Hot isostatic pressing Gas compressor Scouting Spant Ammunition Gear Thrust Rolling (metalworking) Tire balance Cartridge (firearms) Arbeitszylinder Screw Cylinder block Flatcar Electric motor
Typesetting Semi-finished casting products Semi-finished casting products Typesetting Kickstand Steel Kickstand Finishing (textiles) Finishing (textiles) Titan Saturn System Mission Scouting Rack railway Angle of attack Buoy tender Angle of attack Rolling (metalworking) Surface mining Cartridge (firearms) Rolling (metalworking) Forging Surface mining Mail (armour) Material Sheet metal
Starter (engine) Scouting Finishing (textiles) Scouting Ammunition Surface mining Rolling (metalworking) Plane (tool) Tannin Surface mining Mail (armour) Sheet metal Friction Flatcar
Blast furnace Tin can Semi-finished casting products Nut (hardware) Stagecoach Scouting Finishing (textiles) Barque Wire Spare part Surface mining Material Mail (armour) Gun Bulb
Überschallstaustrahltriebwerk Tin can Surface mining Cartridge (firearms) Surface mining Internal combustion engine Ship of the line
Semi-finished casting products Steel Scouting Blast furnace Replenishment oiler Roll forming Rolling (metalworking) Commodore MAX Machine Surface mining Semi-trailer truck Material Van Typesetting Blast furnace Semi-finished casting products Flight Steel Scissors Clothing sizes Scouting Ammunition Sizing Surface mining Klassifikationsgesellschaft Book design
Tin can European Train Control System Steel Steel Mixing (process engineering) Mixing (process engineering) Surface mining Gentleman Rolling (metalworking) Ducted fan Surface mining Material Ship of the line Material
Typesetting Blast furnace Semi-finished casting products Semi-finished casting products Typesetting Ford Focus Steel Clothing sizes Bending (metalworking) Engine-generator Finger protocol Internationale Senefelder-Stiftung Surface mining Cartridge (firearms) Automatic watch Commodore MAX Machine Forging Gate valve Surface mining Ship of the line Rail transport operations Material Flatcar Mail (armour)
Blast furnace Coating Semi-finished casting products Semi-finished casting products Steel Mail (armour) Steel Scouting Überschallstaustrahltriebwerk Rolling (metalworking) Surface mining Spare part Water vapor Mail (armour) Van
Semi-finished casting products Steel Finishing (textiles) Presspassung Sizing Brickyard Spare part Forging Surface mining Kümpeln Material Mail (armour) Water vapor Blast furnace Ship breaking Semi-finished casting products Steel Book cover Finishing (textiles) Captain's gig Barque Seeschiff Sheet metal Saw Rolling (metalworking) Surface mining Cartridge (firearms) Alcohol proof Water vapor Kümpeln Hood (vehicle)
where he left off at rolling essentials so again early the year working .period that is the exit thickness of a and the load required for the rolling and is determined by 2 parameters the Mills stretch and the plastic curve of the material so 1 is related to distortion of the male the other 1 is related to the material response to compressive loads so again where did this come from you opened a mail at this circuit by then gaps as
0 0 there's as you and then you have the material that you want to roll which has a certain entry thickness page 0 right on this graph this defines these 2 points as you the role the material this the mill will stretch this stretch causes the that is a slim year with the with the with the load as I intend to stretch the mail and and the stretching has to be understood very broad sense it includes bending of the roles at it concludes elastic differ plastic bending elastic deformation of the Mittelstand yes but so you get in this this roll gaps will increase and the and there will be the pressure on lolled on the exerted on the ropes again that goes along this line here there's 1 parameter here which is the slope of this line related the slope that is called S and is called the Mill modulus it's something you measure but the the other thing we are measures that the materials response to the compressive loads and that on the the load thickness the diagram basically would be a as it were stress-strain diagram of course string is negative so you compress material strain hardens and as you increase the law so and these are examples here and to the point where you end up is the working .period yes and so you like to I know where this point is because this point will fairy will will change due to the changing circumstances changing circumstances may be changes in the middle and and or changes in the material so let's have a look at what happens to the plastic curve and the mill modulus as we go we have changes in the in the in the rolling conditions so so that this debate cities curse your what called gage meter method gage again gage means thickness basically so it it basically means that when you measurable changes there are directly related to the thickness changes right because of this point is working .period varies along the middle stretch life I intend to win when you measure you will see in a moment in a mail you have loads tests that measure this this peak value and so when these changes it means that you working .period has moved this and it's moved somewhere along this line and that also means that you thicknesses strangers yes they don't you cannot change things began in the mail very few things you can't change independently of such a change the friction things will happen to the load and of the low changes new thickness will change OK so everything is interrelated there no simplistic ways of running a strict Miller rolling sometimes so this very can be very careful the really important message if you're ever in the plant that don't do silly things like people say we have a problem is that followed increase the load right because all things will happen here and may be unexpected things because you think that you can change things independently of each other and so if you change the load just like that you can be sure that you may solve a problem notice of you know some stability with a mail but you'll also change use you sample your Europe euro products dimensions less so you may be running a stable process but then you'll make useless products so very careful 10 the and so there are a lot of refinement to this method of gage media but all of them go back to his cage meter method so for instance but uh uh let's see what happens if but the trip you're getting yes has change changes its thickness for so what happens then with this working .period was so when this due the the uh the changes the the thickness entries to the thickness changes so this point simply moves to the right and would have to my working .period like I arrived here the 2 things happen is that I will certainly see below won't change In the mail and I will also it's and and I will of me not be able to measure it but you can be sure they'll be in exit thickness change so in order to control this answer what do I have to do the important thing of course is the product yes the product is you need to have the
constant exit thickness so the only way you can change this situation is bye increasing the load and so how do you do this you know what you have to you are a mile stretch here to the left OK so would had to do this well by decreasing they rule down content you'll say it will of course you'll do that's right it's it's to get something thicker so you need to reduce smog that's right but the way it works Is this way the you get an increase in pressure in also as you do that get over this dessert this is an obvious situation but let's look at other situations yes OK but for instance some effects rolling but let's have a look at 3 interesting effects we can look at what happens when the rolling speed changes what happens when we changed the tension industry he or what happens if we change the fracture investment now of unexplained this later but when you roll In a mail indeed you would think that is a constant value there it is but the gap changes and the reason it changes this because as you go faster yes it may be counterintuitive but all the bearings In the man which are lubricated all the lubricant films become but yes and so that causes B the role gap to decrease slightly His so it decreases slightly and so you have been increasing the pressure in the load the rolling load and a decrease in your the the product exits thickness yes know you'll say why is this important well when you starting to roll spoke a strip or use stopping rolling the strip that means you have to compensate for this fact yes as you roll faster you need to increase the pressure and so that you you you keep the thickness correct you have to decrease the pressure to achieved the thickness of the correct and so he'll do it the way you decrease pressures you opened your open rolled up a little but these are tiny effects but they do you know they're being taken care of immediately controlled and practice if you have stripped attention yes stripped tension is equivalent to a reduction in the strength of the material so the thickness is the same but as I increase the strip thickness and I see a reduction in the low yes and we know says it's because friction peak decreases it is the energy needed to deform the material decreases the more correct way and and so you see the working .period changes I get less load also left the government product thicknesses changed this so I will have to compensate for that so I'll have to compensate for that I want to have this thickness so I have to move this life to the right so that this becomes might working .period and I achieved the thickness that I want can another this is 3rd diffraction changes hands I'm in a cold strip mill that's pretty much constant and a hot strip mill there may be some variations yes if we increase the a friction it's as if we would make material harder if you want I get it increasing the load I also get and an increase in the so I did that increasing the thickness right so I have gained compensate for that where compensate it I reduced and the role that yes this point the moves up and I can achieve the smallest thickness again so the other the measurement of the load rolling load is very interesting ways to control the thickness of stress you don't have to come to my classes but if you can't you not texting so nowadays it you know good
this will have measurement devices 2 to control the exit certain thickness vary so constantly and wooden very small limits so with which you basically have in a mail it is the 1st of all notes somewhat so basically matches the rolling load that's 1 of the very important parameters yes and that we can the disk into was called an absolute the automatic gage controller yes we have some model there's 1 of 4 the rolling load nowadays also we have thickness gages which are reliable enough to be used in industrial conditions yes but so there mounted a typically a meter or so away from In did a mail Of course this as close to the mail as possible because you're going to use that data to feedback into the control system right so I'm so you measure this and so they're here you basically have the elements you want to control the exit the thickness of the load and the actual segments so you can you have to use this In 2 controller which will then correct things so how this town and this is behind you control this is a this pressure you hard to control the position of the roles as well to the position controller goes into servo valve yes In that case we have a so-called hydraulic Automatic Data control H. GC I'm sorry didn't this is page is you means hydraulic automatic pitch control and as it is basically a pressure cylinders does the servo valve controls the pressure in this In the cylinder and out you increase or decrease the pressure In that Inc along the on the rolls by means of this hydraulic capsule now there are 2 systems To do this there is the this hydraulic automatic gates controlled which basically works with the Pistons and hide prevent boil under very high pressure as yes but would you call so you can also do the load and that the gap setting which is electromagnet electromechanical ways where you basically screwed down the In the roles the busy screwed them that's a much slower system the response time is much lower so the yard you can see here this so for its response time to have a tent of a millimeter change the role gap has it's not it takes the 2 milliseconds for the hydraulic system to get going it takes a few more Ms for the electromechanical systems yes OK so it goes much you continue the response times much faster than and this is a picture here of being the hydraulic automatic gage control system yes and this 1 is you can you can have the cylinders can be mounted below under the the stack or on top of it the 1 here on top the picture here the top mounted hydraulic system this is nice you can see it's mounted on the frame of the world and these then the user the flat parts here actually exert pressure on the rocks so even if you would cut this through yes I'm so you have here you have to cylinder body has nearly
halved this distance OK and end and here you have boiled and the and the increasing the oil you can make this persistent move up and down and this the trust plates in this flats plate pushes on not directly on the role but on what we call the roll truck rolled truck is where you mount you mount role role is mounted on a truck which skull truck and so you press on this press down on this job and you will increase your you decrease the pressure can't and it's a would you basically get it you can also directly but you also measure things on the cylinder yes you can measure the pressure of the oil pressure directly and you can measure the position of this L both Of this trust as opinion you can feed this back to the setting yes and then you go on fire so far Dean
control you can control servo valve yes which basically increases or decreases the pressure inside the cylinder which makes the cylinder move up in order to 10 In the case of the screw down system which it's different to their you you basically have a mechanical system and you have warned years years so here we have you have to cost block which rests on the truck and then you have instead it mounted inside the 1 of them would do the body of them the stand rolling stand you have but not brew has that weight that is threaded threaded part and then you have a screw that is also threaded of course which turns into their threaded parts of its business group can move up and down and when it does move up and down it exerts more or less pressure on this thrust block and how does it move up and down while it moves Vial a deer yes there is a gear here as and this year this basically itself it's important to the we'll yes this is activated bye I warm Dear also that's just threaded bar the moves in 1 direction or the other and can increase or decrease the position of this this crew here social issues 3 dimensions here see you have a motor here yes the motor has had this motor makes this part moved up or down and exert pressure on the Net on the truck here concedes he misses France a backup role here you have in this particular instance you load cell is mounted here and this is the thrust bearing presses down on the and this gives the load sell this year you have to scroll down do not that's mounted in the in the frame of the mail and here is the screw down the actual screw dance moves up and down and and this is how you make it move with is electrical motor here OK there's a lot more to males than just
exit thickness control the products have to be not only have the right to dimensions of there have to be strike or if this strip products that we have to make sure that their flat and so will go into that in more detail later on because that's a bit more specific leave related to stress some product and we will talk about Strip properties which are very very important few things up that may be of interest for the next lecture is found you know when you when you make the formations at high temperatures and you have a piece that's 25 cm in thickness and you have to turn it into something that's 5 mm in thickness know how you know how much how long does it take this well In a typical the hot strip mill you will go through that will sleep the roughing stand and there you will have about 6 to 8 roughing it the status and the finishing rolling you'll have about 7 OK so in total we're looking at 14 15 the formation steps In this case uh of hot strip mill the temperature goes from about 11 52 How about a thousand 50 in this roughing the rolling and from thousand 2 850 people their ballots in the finish and the reduction per pass In the roughing it 20 to 40 % that you give into finishing it can be high at the start and it'll be in the lower and can be much lower 5 to 15 per cent strain rates of very different in the rough we've got 2 0 2 20 5 typically 5 25 being the high end and in the finish area goes up to 100 the 2nd Inter pastimes that means How long does it take between passes into roughing 10 to 20 seconds into finisher much shorter 3 To half a 2nd and the reason is that the roughing mail is a reversing a mail the finishing mill is a tandem tender means you have that you you roll you passed straight through different mills stance OK so it's something that will let you have a look at this virus yourself can have a look
at this but you can actually you know calculates that uh that the number of reductions 15 years is actually very reasonable and very it's to be expected so did that the again the steel mills are are based on design right it's not like they all look like this because we've always done it like this this it's not like they're on so that the ways You you you roll slabs is because you have the schedules of rolling has and the final thickness it is determined by d reduction prepares in which are dependent on entry conditions despite angles of my a strip the type of steel that will be rolled stands strength as to certain things certain things it cannot be rolled in certain the rolling males because the for instance to the rolling loads are the dead are required are too high so the reduction yes that you can have applies as in in total the total reduction this is of the order of 1 2 2 it's it's a total reduction it's very large think about if you're involved in making steals the reduction that you give to your material is of the the order of the maybe 10 to 20 per cent 30 per cent and if you have exceptionally mobile material it'll be about Nelson 60 per cent 70 per cent at structure OK so in in in the males you you know the total at deformations can easily go up to them to students to 200 % but now you cannot rule things like that you need a rolling that is you have to do the reductions yes we are limited by the fact that you want to avoid cracks the debentures in particular and you also tend to reduce the amount of reduction you give because that allows you to improve strip quality the quality so you can have maximum amount the higher amount of reduction indeed intermediate passes at the beginning you can't get large reductions because you're going to have edge cracks at the end you want to protect the surface but so you don't do much do smaller deformations at the start and that the party that at the end of the rolling hills so say where is if you want to calculate how much passes you need to achieve a reduction if you for a total reduction if you have a mean reductions hours typical mean reductions in so I'm surprised if you do the calculation for 25 cm to 5 mm news then you can calculated the total reduction is the mean reductions to power and and being the Andes are true strains by the way there and being the number of passes so if you said mean reduction 1 . 5 10 and is 10 passes and you can see you can assume different amounts of that total defamation and different amounts of mean defamation and you see that as expected you will have between 10 and 15 steps of world so that an example here the actual measurements of of the
year the time of the rolling there's the thickness that you achieved and the amount of reduction and so for each a mail In a hot strip mill this is the reversing mail the intermediate roughing mail and then finishing mill and you can see that you you get all while the reduction yes thickness reduction is in the roughing them and much less thickness reduction in the finisher but if yes if you now measure the reduction yes the percentage and reduction you actually see that the the amount of reduction here is actually not so lot which has this will be of the order of nuns and and here at the start of the finish you give all of a considerable amount of reduction in comparison there's also a thing that's interesting here sq do the rolling hills it it takes time has to do it you start rolling and then you say so and so for instance here and the Phoenicia starter Frohling end of rolling about 100 seconds etc. so you can also see that here and a writer that's that's about to end that should we refute some some things that will be useful in the next
section of the camp where we will be looking at hot strip mill and and how we make products and in so the year the hot
strip mill that will be describing or so-called 4th fourth-generation Mills a very common in in integrated mills N they consist of several major 1 is the 1st part is reheating furnace where you you start from slabs then you have what we call the rough defamation roughing Mills you changed in that steps be /slash to the bar an intermediate bark and then you go into the finish Phoenicia which is attend a mail then we go into the cooling section and the coiling section to every step has its specificity and will discuss them it's interesting to focus on hot strip mill because their common and even if you look at the bar a mail or wire a mail this structure the hot deformation section yes is very similar as you always have reheating where you reheat the billets Florida blooms there's always section where you do a relatively rough shaping of the material and then you you finished a product To get the ends sighs and this is followed by a very important cooling and calling section but the cooling section is essential because that is where the transformations happen that you usually you role in the Austin they take their range so the FCC and when you I have the product is isn't low-temperature yes but it's Varitek so In between yes you can control the jury in the calling stage you can control the records students again doesn't want
to it's close supporters and
Newfoundland but in this case instance was repentance doesn't want to hold the line on which so hot strip mill hot
strip mill and they will
also look differently sometimes because of the types of products that are being processed so let's
go through these general points
you have strip mill is a process where we roll slap at a temperature and in a state where it will go through we crystallization if it's before so the Steelers the forms and what we would will happen is we change the Austinite grain size and end in the end product isn't semi-finished steel column that's already a product there is a market for this year's so did the quality of this intermediate product is very important to us so will prove will will talk about the principles of these males a standard designs and interest mentation automation systems that are important and it will also talk about how the slapped quality has has an influence we will discuss all the uh it features such as slab reheating the requirements the design of the surface of the eye and reheating furnace a roughing and finishing mill designs this is scaling stricken with control box "quotation mark books technologies etc. and also talk about a little bit about roles that we use it and then we will talk about it give some some examples about what the impact of the processing on the quality but will have a separate section where we actually discussed products and how they're made in hot strip mill so again what does the hot referred to in hot strip mill the Rexall flight isolation temperatures so we everything is above 60 actually all the processing of in the hot strip mill is a this temperature by the time we Coyle the product it's very often above this temperature around temperature so the Rexall isolation is very important to me and you know what this means this means that you may deformed the material but in between the defamation steps material recreates
Oh no defect density we crystallized material In if you work in a large steel plants there is the
because he's a very large plants that you may get the impression that the hot strip males the clients of the Hofstra Mills Colstrip males and that's a hazard that's the only thing you have to worry about that's actually you know important to realize that this is not the case against but we have been very high customer demands yes in terms of material properties quality and consistency and so hot strip mill design years it is actually very much determined by what is the original product mix that of hot strip mill was supposed to supply so the mechanical electrical dimension and etc. at the O 2 Imation is all determined by what kind of products you want to the producer and it can be very different knows so too the UN initiated person it's all looks like coils yes but you can have very different product mix this an example here for 2 plants in this 1 here has all kinds of constructional steals formidable carbon steel I have steel complete etc. and so a large variety applications In this 1 here yes it's very different we see that that three-quarters of the production is devoted to form of a low-carbon steels and stainless steel it's OK for this to be a very different I would in different way of running and etc. so as I said most of these the lines
look very similar there's and 5 0 compared here we are hot strip mill that are in operation so important which ones they are sir the it's always been important parameters and hot strip mill is that know what's kind of slabs which decides whether the dimension of the slabs that you can process has in terms of whether thickness and like you see here for its hot strip mill length maximum length 9 . 6 OK hot strip mill to ISS 15 meters "quotation mark strip mill 3 12 the West is also very important yes because that will tell you what is the maximum width of the product that you can deliver this line here hot strip mill 1 1620 hot strip mill to 2 meters 20 hot strip mill 3 a little less than 2 meters and so on this is hot strip mill is much of a less well equipped to produce automotive the steals because of automotive industry they're interested in very she steals because then they can make very large stamping say yes this and this is improved the productivity and the quality of the did the material the products so get and stretch the cost of which is determined by the slab sides here the thickness also you can see here to up to it when when you look at the thickness the performance of a hot strip mill with people like to look at is how things can you go it could be that allows you to then hot strip back this and so on you can see here and in general of hot strip mill lower the boundaries about 2 millimeters even that will be as difficult and but you see here that I love it you can go down to 1 . 5 as 1 . 2 it's very low and typically 20 to 25 mm in thickness hot strip mill don't like to produce Fehrnstrom because that's very lean that decreases the productivity and so in general are a doesn't make you popular when you developed within Hot Strip project then strip products are very much ideal or contact strip many males has and will talk about the use of technologies next course in the 5th fifth-generation culture go away it is also very important because it's a reflection of the productivity you can achieve how much you can produce I use your line number 245 Tom so that's a very heavy equipment that you need for instance when you coil material but the specific weight of the coils it is typically 20 currently for many other males 23 . 6 this opposite very high so that's a maximum speed of the processing that's the the speed that the strip will have at the exit this is a very high values here and 23 were talking about I don't know exactly that many kilometers per hour 4 hours of very fast and the capacity of course as you can expect that line number 2 will have very capacity about 4 million tons of steel can be processed are here know what 10 meters per 2nd is 36 of 20 meters the 2nd is is very high very high speeds now OK now it just to give you an idea about what what this 2
. 4 million tons per year or 3 . 6 how much is with what is that we know know what it is but a hot strip mill and good hot strip mill Hi high-performance would would would good equipment these days can make 5 million tons of struck as and if you so that the thickness is about 4 mm and it's the width is about 13 hundred 40 millimetres Mendes the total stretch the length that produced per year it is 133 thousand kilometers just so that means you can go around the world the a few times and 3 types with this trip just from 1 and so it's a huge amount of material that is produced Duncan but and when we talk about this for generation males the original designs are not at all did original designs of the 80's yes there they actually are and very good way of producing steals in terms of cost but usually they will have will see reversing rougher yes but they will be there will they will be equipped with will see that again with walking being furnaces they will have have the edging heavy edging allows you to reduce the width of your /slash yes and so it allows you to change you have a variety why the product which With the same Castor sighs and then there is a lot of automatic control inspectors modern mills have a hydraulic automatic gates control there is role bending role shifting and prosperity technology we see that in late wrong this is just technologies that allow you to control the profile the flatness of your stress and then we will also see that there are technologies which are developed and installed to get the temperature home which NAT In your material perfect almost perfect and and 1 of these technologies is the coil box can to get out just think case you'll you'll find the focus on hot strip mill a little bit too overwhelming so continues hot strip mill mills make out probably half of the the hot strip mill that we have in the world knows there is still 1st things like many mills and will talk about this because this is a fast-growing segment of males and we will we will discuss this can so just in a bird's view 1 of the the fourth-generation mail
it starts after you have your slaps never come from the continuous casting the slabs are usually story yes for processing and this and this lapse here that's where this the steel plant and but the slabs are allowed to cool yes and then they're processed in a specific way which would then we will discuss later here and there and then taken into the reheating furnace there are roles here in the reversing milk there may be a year this intermediate coil box and then there rolled in the heart the finishing mail the tandem mill here the between the Phoenicia and coiling it's not shown here there is the the cooling section get but which you get after this process is stodgy calls here and you can see them if you compare differences in the same coils after they have been cold rolled in as you can see they're black often the called black corals and because of that said the hot rolled coils here in this instance because so we'll be talking about that part of the the processing and the department comes after words to pickling the
cold rolling the annealing and maybe the coating will talk about which which leads to flat-rolled cold-rolled products will will discuss in a separate section because to some useful vocabulary when we started because in the field of people you know have their own
vocabulary to describe the parts of the obstacles was slapped you already know what this says is it's a rectangular piece of steel 20 25 centimeter thick as a meter in width and about 10 meters in length a buyer is what happens to me is the name you give to the slab after its passed through the Rafah yes 18 and the the rough is such that you go from centimeters to about 2 . 5 centimeters so that's a reduction of 10 that means that this reduction of 10 is translated in aligned increase of 10 or so you go from 10 meters 200 meters so that so the bar is not typically a few centimeters thick and 100 meter long bunker the strip searches would happens when the bar has been has passed through the finish and is now thin enough so you can wrap Quayle but coiled ranch piece of string in V as a vertical scale breaker it's it does 2 things it breaks the scale on the side of your /slash but it also reduces the width of your slack that's the roles of vertical not horizontal because of its vertical and scale breaks although they do through thanks to break the scale and skill is sign that Europe is a smaller role that make sure you've you do with it you may get some bulging at the edge this is controlled the rafters are usually in the technical literature you write Parrish R 1 R 2 or 3 yes that's the way we designed roughing males and so on the finishes are usually referred to as 1 of 2 A 3 A 4 and A 7 years the designation of finished and when we talk about the scaling yes we talk about removing of scale and skill is box oxide in this or the Thermal Oxide that is formed on stretch during processing it's of high temperature it's an air it's firing so it readily oxidized so that's that's also an issue there needs to be taken care of and that's so the scaling is usually done with high-pressure water right and this is just sometimes you have foreigners did use order the dimensions of it's nice to have some conversion table so that is a let's start at some of outcome figure generals configurations so this this there's a configuration 1 here which is very traditional so you have a reheating reheating furnaces typically 2 3 again depends on your production so you slabs of fed into this furnace then knew the scale of the this land as they come out of the furnace then you do you have a sizing edges determines the width of your slap you go through roughing males which to 1st reduction you go again from 25 centimeters to 25 mm this transfer bar it's what you have here you UDC you you cheer cheering will see that the the front end of the a bar and the tail end of the bark are not straight yes there been can of shapes that can be around that they can have the shape of a fishtail you have to cut this off and so to you you cut to material here and then you pass through there the tandem mill to finish a mail cooling table which week we call the run out table and because the district is a really running at high speed outs after the the finishing mill and a new court and you can have too 1 2 or 3 quarters depending on your production capacity and depending on your investments capacity because squalor are very expensive right adjusted the interesting thing you may want to remember if you are involved in research in your career if you need material From a steel plant it's always very hard To get materials and particularly want samples this is very hard to get samples from from around from coiled material yes because they have to do they have to cool and cut it has however you should always remember that you can easily get samples after shears yes and very often they are places in the plants where people share the stretch yes and they don't have to make any potential effort to I want to get to cut this year only effort you have to make get a sample this right and that's more easily organized and it costs much less than 50 need samples from the hotmail typical it get them after the ship yes and if you want laboratories on that and there's plenty every every every now and then /slash yes is you cut to front end and the tail end of the slaps you can get samples there right the writer this is so the more details saying yes this is here the 2 this white waited a half this because in this case you get a better idea of the actual dimensions because here it looks like the finishing mill is a very wide and and there's very little distance between the the the sheet the roughing mill and the Phoenician actually you need a lot of distance between the at the finish the roster and a finish the reason why is because you have a bar a bodice 100 meter long right so that's why this distance here is 120 meters long and on the other hand the finisher is actually quite complex 30 40 meters that's enough and again the laminar cooling will be long the cooling will be long typically be well it's it's it's not to that fully 180 meters it'll be about 100 metres yards but it and the reason why is because you want to control it's very precisely the the cooling past of your material for I see that it's a quarter past 12 and would come to the end of the session today and I thank you for your attention with a


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