Modern Steel Making

[Applause] many many things are vital to our living and to our standard of living only one but a big one is steel we could do without it but not as well because it does a lot of things for us try naming them sometime you'll find it hard to stop the steel mills are amazing complexes dependent upon mountains and minds of iron ore high-grade coke baked from bituminous coal limestone a common stone but as costly as any to transport and utilize making good steel isn't easy it takes the best materials the best machinery the best men men at the blast furnace the open hearth furnace men of science men in the rolling mill men of the electric arc furnace men who are proud to be called steel men it takes raw materials from all over the world to make steel this iron ore may have come from any one of ten states or distant mines in other countries the first step in producing steel is to make iron in the blast furnace raw materials are taken to the top of the furnace and skip cars loaded at the bottom of the furnace this car carries raw iron our sometimes the ore is centered or pelletized to facilitate blast furnace operation this skip car carries coke coke produced from coal it may have been mined in any one of 19 states the next car carries limestone that may have been quarried in Alabama Michigan Pennsylvania Ohio or Utah or coke limestone charging a blast furnace that can produce more than 3,000 tons of molten iron every 24 hours within the furnace and inferno rages a man controlled inferno of chemical reactions in diagrammatic animation we see blasts of hot air raise the temperature of burning coke to 3,600 degrees thereby supplying the heat required for the chemical reactions to take place carbon dioxide is produced and reacts with the excess carbon present to produce carbon monoxide gas that is carried up the furnace near the top of the furnace the temperature is only 700 degrees Fahrenheit as the burden settles downward and the temperature increases greatly the lime from the limestone combines with impurities from the ore in the coke and carries them to the bottom of the furnace as slag the slag and molten metal collect in the hearth of the furnace the lighter slag on top the heavier iron underneath every few hours the slag is drawn off through the slag nudge several times a day the molten iron is cast from a separate opening [Music] 400 tons of white-hot iron at a time for this friends the gushing stream of iron runs into an insulated transfer car where it is kept molten transfer cars move the molten iron from the blast furnace to the steelmaking furnaces where the iron has changed into steel here are the transfer car tips to pour the liquid metal into a ladle which will carry the hot iron to the open hearth furnace the open hearth furnace is a versatile tool for steel production before the furnace is ready for the molten iron a charging machine loads the furnace with limestone iron ore and steel scrap scrap comes from old automobiles machinery railroad cars steel rails and other pieces of iron and steel that have outlived their usefulness the ladle of molten iron from the blast furnace is added after the limestone iron ore in scrap scientific controls help the melter meet the most exacting specifications to get a better look at what happens inside the open heart let's diagram it with the top off we see that the molten mixture is held in an oblong shallow hearth burners at each end of the furnace alternately send long tongues of flame across the surface of the mixture searing flames raise the temperature of the charge to about 3000 degrees and chemical reactions take place the change iron to steel the [Music] appearance of the slag on a heat of Steel is important to the melter there is no substitute for experience it takes a real pro with all the help he can get from scientific instruments to judge when the chemical reactions have gone far enough to give the steel the exact composition required by this time the melter has a lab report which he checks against the production order this heat meets specifications a parameter gives him further information measuring temperatures far beyond the range of an ordinary thermometer that cable hanging from the back of the handle runs directly to the control panel with only a glance the melter has to be able to read and interpret the recordings of precise instruments instruments that tell him what he needs to know with a signal to his crew the melter goes to the tapping side of the furnace that whistle says be alert the tapping hole is located at the rear of the open hearth furnace the man places the shaped-charge that will blow out the refractory plug and release the white-hot steel the wire from the charge is connected to the battery the melter watches the steel carefully to be ready to add the alloys that are specified for this particular heat carbon steel can be changed to make Steel's for special purposes while the addition of such elements as chromium or nickel introduction of oxygen by Lance improved the efficiency of open hearth production to a significant degree but its most efficient application is developed today in the basic oxygen process a basic oxygen shop can turn out high-quality steel much faster than open hearth furnaces [Music] Moulton hire has charged into the basic oxygen furnace followed by scrap dropped into the mouth of the vessel in the basic oxygen process the chemical and physical reactions take place very quickly after about 20 minutes the nature of the flames confirmed by computer calculations indicate that the reaction is complete and the furnace is ready to pour another important tool of steelmaking is the electric arc furnace this is used to make stainless and many other special Stevens scrap is its basic diet after the furnace top has moved aside and the furnace is charged with scrap an operator uses fingertip controls to direct powerful machinery that slides the huge top back into place when the current is turned on the power surging to the electrode sways the heavy cables in fact you could light a fair sized city with the electricity used in a single electric arc furnace here to the melter is the master chef who controls the recipe for the special steel he's making carefully measured amounts of nickel chromium tungsten vanadium or other alloys are added do give each customer precisely the kind of special steel he needs the charging machine adds limestone and other materials to remove impurities and the furnace is ready to tap the melter goes to the pouring side he pushes a lever and the whole furnace tilts to pour the steel into the waiting ladle whether the steel flows from electric furnace BOF or open hearth it moves next to the teaming area but this is only the beginning for different Steel's acquire still more varied qualities in the treating and shaping it to come here steal from an open hearth furnace is poured into waiting cast iron molds then the ingot molds are moved to the stripping stand here huge hooks remove the mold from the ingot [Music] [Music] the ingot is still hot but solid enough to hold its shape next stop is that the large furnace is called soaking pits where the ingots are brought to uniform high temperature for rolling [Music] [Music] when the rolling mill calls for steel the ingot is ready 2,300 degrees hot top to bottom inside and out [Music] in these operations ingots generally range from 4 and 1/2 to 24 tonnes that's from 9,000 to 48,000 pounds [Music] ingots are roll into a bloom or a slab blooms give the world structural steel [Music] structural steel for skyscrapers bridges and other structures looms are also rolled into billets another common shape of semi-finished steel billets are formed into tubes and bars of many shapes and sizes from which manufacturers make drills hand tools and Hardware billets to make rods rods to make wire steel wire for baskets paper clips coat hangers fences window screen and countless other things slabs from ingots can be rolled into plate plates may be used in the strong Hall of an atomic-powered ship storage tanks a giant crane road-building equipment or heavy machinery [Music] conventional processing now goes to work on the ingot skilled men manipulate the mechanical monsters that shape and form the ingot into slabs some slabs continue on their way immediately other slabs are kept in storage until they are needed before being further rolled these slabs must be reheated to the proper rolling temperature in the reheat furnace when the slab reaches 2300 degrees out it comes headed for the scale breaker then it continues through the roughing stands the slab is squeezed flattened and edged as it passes through one set of rollers after another the slab that was once 7 inches thick and 12 or 15 feet long now is a sheet of Steel over a quarter of a mile long and only 1/16 of an inch thick traveling about 20 to 25 miles an hour the sheet races down the run-out table where water sprays drenched the steel with a thousand gallons a minute to cool up to proper coiling temperature the steel at this stage is known as hot rolled which there are a variety of uses however most steel is processed further it may be pickled to remove oxide it may be cold reduced annealed temper old galvanized or coated with tin more and more a cold rolled sheet as seen here is being shipped to customers and huge coils customers stockpile coils right in their own plants to have a supply of steel on hand when they need it [Music] steel like this but with many technical variations according to the needs of customers continues now in every direction to lend beauty and style and strength to automobiles to provide tough steel that will stretch without breaking and form the washtub of a washing machine to make billions of cans each year to bring us beverages food and countless other products [Music] to give polish and durability to kitchen cabinets and appliances or to form the clean and colorful surfaces for the buildings of today and tomorrow no other metal perhaps no other material is as versatile as steel and yet it is not easily produced the investment of many thousands of share owners is required to build and keep modern the Mills the imagination and patient continuing research of many trained minds is essential to the development of new and improved products and methods but above all steel challenges and attracts the dedication of thousands of men proud to be called steel men proud of their contribution to a world in which the progress of man is so closely associated with the progress of steel [Music]