Steel : The Metal Giant (1981)

foreign [Music] what do skyscrapers have in common with farm implements film projectors and bicycles [Music] they're all made with steel the most produced most used and most reused the giant among metals [Music] one of the wonders of the modern world that we take for granted is steel form it into the hull of a ship and it floats shape it into beams and it holds up the tallest buildings produce it into bars and people can make tools and wire and machinery make it in thin sheets coat them and we have stoves refrigerators washing machines Automobiles and trucks modern steel mills are large places with everything from Research Laboratories to complex equipment for testing and removing water and air pollutants they employ men and women of all Races in a variety of skilled jobs [Music] it would take hours to explore a steel mill and see all the kinds of steel made here so let's concentrate on one product sheet steel the kind that goes into cars trucks and appliances sheet steel comes from the mill in large coils or rolls do you know what this strong shiny metal is made from rocks that's right rocks mainly iron ore Limestone and coal it begins in the iron ore ranges near Lake Superior with the scooping up of a special kind of rock called taconite the rocks are crushed the iron ore is removed and formed into pellets Limestone also is found in abundance in this general area after being mined it's crushed into smaller stones for shipping or boats carry the Limestone and iron ore pellets through the Great Lakes shipping convenience and the need for lots of water are two reasons why so many steel mills are located on the shores of the Great Lakes Cole the third major ingredient usually arrives at the steel mill by train now we have the basic materials at hand in simplest terms there are three steps in steel manufacturing make iron make steel shape Steel for making iron the coal must first be changed into Coke [Applause] the goal is placed in airtight ovens a row of ovens such as you see here is called a Coke battery inside each oven the coal appears to be burning up but it isn't undesirable elements are being baked out of it after being quenched with water the lumps emit harmless steam the coke will burn with more intensity than coal now we're ready to make iron from the huge stockpiles operators and batches of Coke Limestone and iron ore by conveyor to the top of the blast furnace This Modern blast furnace is as tall as a 30-story building it operates continuously and can make up to ten thousand tons of iron a day it looks calm from the outside but it's like a controlled volcano in action with animation let's see what's going on inside the blast furnace is so called because of the continuous blast of hot air it receives this air causes the coke to burn so intensely it melts the iron ore and limestone unwanted impurities in the iron ore cling to The Melting Limestone and Float with it to the top forming a layer called slag and leaving the heavier molten iron at the bottom there is a notch for drawing off the slag and a lure hole for tapping the molten iron now we're in the cast house around the bottom of the blast furnace as everywhere in the mill workers are protected by special clothing and safety equipment a tackle is opened in molten iron pours out and flows along the path prepared for it it flows into special Railway cars that are lined with bricks inside like giant thermos bottles they keep the molten iron hot as it heads toward the next step making steel the main ingredients for making steel are the molten iron and scrap Iron and steel in the form of scrap can be recycled over and over several types of furnaces are used for making steel the modern one from which our coil of Steel will come is the basic oxygen furnace called the bof from a room close by workers operate the basic oxygen furnace with the aid of computers the bof is like a huge pot only the upper part is visible at this level as it tilts to receive the scrap [Applause] thank you it rotates to spread the scrap over the furnace bottom then tilts again to receive its charge of molten iron it will turn these ingredients into 255 tons of steel in just 33 minutes a pipe called an oxygen Lance is lowered into the furnace it will blow oxygen into the furnace at high speed creating intensity often 3000 degrees Fahrenheit the oxygen combines with carbon and other unwanted elements eliminating them from the molten charge with those removed the iron becomes Steel other metals or Alloys are added to make the type of Steel desired during the process samples are taken of the molten steel for immediate testing if the tests are satisfactory the furnace is tapped [Laughter] the end result is a ladle of Steel of one specific type nobody can use 200 tons of molten Steel so next it must be cast or solidified into a form convenient for shaping a modern energy saving method of shaping steel is called The Continuous casting process it changes steel from a molten to a solid state in one continuous action here's how it works from the ladle the molten steel pours directly into a copper mold which is water cooled the cool mold causes a skin to form on the surface of the steel the skin becomes thicker as the steel cools from the outside toward the center gradually becoming solid throughout from one type of Caster the steel emerges in the long narrow shapes called billets from which bars are made from another Caster the hot steel comes out in a wide thick slab which is cut into desired lengths our sheets deal will be made from this slab first it is reheated then begins its Journey Through the hot strip myth we're about to see our thick slab rolled into a thin sheet nearly three thousand feet long operators with the help of computers control the speed of the slab and the pressure of the rollers each set of rollers compresses it a little more and in a half mile run the slab goes from thick to thin rolled into a coil it is now suitable for many uses but it is not yet our final coil of Steel as we've just seen while steel is hot rollers can compress it into another shape in other parts of the plant rollers are squeezing steel into structural shapes into bars Long and thin meanwhile our coil of Steel has cooled after being cleaned it's fed into another Mill for Cold Rolling the operator sets the pressure to bring the steel to the exact final thickness desired Cold Rolling has hardened the steel to make it suitable for forming into many shapes a cover called an annealing chamber is lowered over the coil to reheat it evenly after annealing the steel will be lightly rolled again finally this steel order goes through the galvanizing process receiving a zinc coating to protect it from rust and corrosion now the mill work is done the rocks have become sheet metal and who knows steel from this very coil may have been shaped painted and made into the body of the next automobile you see foreign