Steelmaking

“ We still speak of boiler iron, railroad iron, iron ships, etc., but these names are reminiscent, for in the construction of modern boilers and modern ships, steel is used exclusively. In the past decade it is probable that no railroad rails even for the smallest and cheapest of tracks have been made of anything but steel.
The last half of the nineteenth century has been one of triumph of steel manufacture and production in America, and at the present time the United States stands head and shoulders above any other nation in this industry. ”

“ One portion of the works which seldom fails to interest visitors is the steel works, which, at the time of their opening in 1864, consisted of a converting house with two converters, a cogging shop, and a small forge, but have since been greatly enlarged, the steel-making plant being now capable of producing 50,000 tons of steel per annum, besides which there have been added a large forge, iron, brass and steel foundries, rail- rolling mills, a boiler shop, and several repairing and other shops. ”

“ No matter how we try, probably none of us ever realizes the immensity and importance of the iron and steel industry with approximately 460 huge blast furnaces here, 5000 cast and malleable iron foundries, about 1000 Bessemer and open-hearth steel and some 3000 puddling furnaces, and the many thousands of factories which each day are turning the products of these into rails, plate, wire, pipe, and the infinitude of finished articles which enter into and are mighty factors of our civilization. ”

“ One naturally wonders how it is possible to mine and carry these ores to the shipping ports of Duluth, Superior, Two Harbors, Marquette, Ashland, Escanaba, etc., put them aboard ore carrying boats, transport them by steam power to Milwaukee, Chicago, Gary, Detroit, Cleveland, Pittsburg, Buffalo, and the many other iron centers and convert them into iron and steel at a profit. This, of course, is only possible because of the inventive genius of man. For every operation ingenious machinery has been constructed which has brought the cost of such operations to its lowest terms. ”

“ The story of railroading leads naturally to that of progress in iron and steel work generally, which has been extraordinary during the century. Of inventions in this direction perhaps the most notable is the Bessemer steel-making process, which converts iron into steel by the direct addition of the necessary quantity of carbon, and has had the important result of making steel cheaper to-day than iron was not very many years ago. In iron-working machinery the progress has been very great, and in no other field has the genius of the American inventor been more conspicuously displayed. ”

“ The steel is cast in lots, weighing in some cases as much as 75 tons, in enduring cast iron moulds into very large ingots, which with their initial heat are immediately rolled down by a series of powerful roll trains into their final shape with but slight wear and tear of the moulds and the machinery. But in addition to the greater cost of steel founding as compared with rolling there are two facts which limit the use of steel castings: (1) they are not so good as rolled products, because the kneading which the metal undergoes in rolling improves its quality, and closes up its cavities ”

“ From the day when steel was made “by the spoonful” to the present, when the great “Steel Trust,” with its thirty-eight Bessemer converters and 334 open-hearth furnaces, is capable of producing some 65,000 tons every twenty-four143 hours, is a far cry reckoned in terms of industrial development short as the reckoning may be in years. The pioneers of steel never dreamed of the enormous proportions to which the industry would grow, the innumerable uses to which the metal would be put.
What is steel? Iron that has been refined and hardened by processes in which heat plays the most important part. ”

“ However the steel is made the ingots are reheated and either hammered under a powerful steam hammer or pressed in an enormous hydraulic press. This greatly improves the quality.
The steel can then be rolled into plates, bars or whatever form may be required.
The finer qualities of steel such as are used for making sharp tools are made in quite another way. Instead of being made from crude iron by taking out the carbon, the materials are the finest qualities of wrought iron and charcoal which are mixed together in the correct quantities and melted in a crucible. ”

“ Bars of blistered steel that have been the most highly charged with carbon, and are therefore the hardest, are broken into short pieces,—those being put together that are of a like hardness,—and placed in pots of fire-clay, about thirty pounds in a pot, with covers fitting perfectly tight. The pots are placed in a furnace, and the steel in them melted, when it is poured into cast iron moulds, and made into ingots. These are under a tilt-hammer drawn into bars of all sizes. This is cast steel, and it is evident, must be of uniform quality and hardness. ”

“ The industries connected with iron and steel making in the United States are conducted in a much larger way than in Great Britain and Germany next in rank. The increasing use of steel by railroads, in highway construction, ship-building, the making of engines and farm machinery, and for large building is causing many persons to wonder how long this progress can continue unhampered. Is there no limit to our high grade ore and to the development of the gigantic enterprises dependent upon coal, iron and steel? ”

“ There are several plants of independent steel companies that run on a three-shift, eight-hour basis; [Pg 153] and the steel mills in England, France, Germany, and Italy operate with three eight-hour shifts. The long day is not a metallurgical necessity, therefore. The metallurgical explanation of the twelve-hour day, however, is this. The process of making iron or steel is necessarily a continuous one, because the heat of the furnaces must be conserved by keeping up the fires twenty-four hours a day. ”

“ Outside the car window, ore piles were visible, black stacks and sooty sheet-iron mills, coal dumps and jagged cuts in the hills against greenness and the meadows and mountains beyond. There were farms, here and there, but they seemed to have been let in by sufferance amid the primary apparatus of the steel-makers.
What an amazingly primary thing steel had become in the civilization we called modern! Steel was the basic industry of America ”

“ Whenever we have the good fortune to intersect India with railroads, steel-iron will be among the number of our enlarged imports.
The hard and elastic qualities of steel, known as “temper,” are obtained by heating and then cooling rapidly. For this purpose baths of mercury and of boiling oil are used. Some waters are supposed to have peculiar virtues for tempering steel.
Case-hardening, a process much used for tools and plough-shares, consists in superficially hardening cast iron or wrought iron by heating it in a charcoal crucible, and so converting it into steel. ”

“ Now in the series of operations, the blast-furnace, puddling and crucible processes, through which the iron passes from the state of ore to that of crucible tool steel, it is so difficult to detect just which are the conditions essential to excellence in the final product that, once a given procedure has been found to yield excellent steel, every one of its details is adhered to by the more cautious ironmasters, often with surprising conservatism. ”

“ The steel is made from ore or from a combination of different kinds of iron, and, by peculiar devices for economizing the heat of the furnace, the process may be continued so long and regulated so carefully that a product of high quality may be turned out at a moderate cost. The result of all these processes has been to change steel from a luxury to a necessity of modern life. Modern mild steel is 40 per cent stronger than iron, and is tough enough to be tied in a knot or punched in the shape of a bowl when cold. ”

“ The best, because most recent of the good elementary text-books on iron and steel. It is behind the times in regard to American practice, but contains a great deal of important information, clearly expressed. Covers iron ores, their physics and chemistry, construction and working of the blast furnace, foundry practice, puddling, forging, the Bessemer, open hearth and crucible processes, special steels, the testing of steel and protection from corrosion. Its sketch of the structure and heat treatment or iron and steel is very incomplete. ”

“ Among the improved processes invented of late years for the manufacture of steel are those of Heath, Mushet, and Bessemer. The last promises to effect before long an entire revolution in the iron and steel trade. By it the crude metal is converted by one simple process, directly as it comes from the blast-furnace. ”

“ Then the steam-hammer shed, in which nothing but forging is done, was a flourishing place. All the wheels for the engines and waggons, together with piston rods, driving gear, axles, and cranks, were made there. These are obtained elsewhere now, some in England and Scotland, and other parts from abroad. Steel has superseded iron in a great degree, too, being harder, tougher, stronger and cheaper. The combined skill of the chemist and scientist has simplified the manufacture of it, and it is to be obtained in large quantities. ”

“ Hence, tougher and more fibrous grades of soft steel termed “Machine” steel, are employed, meaning that the steel is especially suitable for the working parts of machines. This class of steel is of a lower grade than that known as “tool” steel. It is softer, works, both on the anvil and in the lathe, more easily, and will bear heating to a higher temperature without deteriorating. It approaches more nearly to wrought iron, and is sometimes made of so low a grade as to be scarcely distinguishable therefrom. ”

“ Modern tool-steel practice has changed from that of the past, not by the use of labor-saving machinery, but by the use of scientific devices which aid and guide the skilled craftsman in producing a steel of higher quality and greater uniformity. It is upon the intelligence, experience, and skill of the individual that quality of tool steel depends.
HARDENING HIGH-SPEED STEELS We will now take up the matter of hardening high-speed steels. The most ordinary tools used are for lathes and planers. The Page 172 forging should be done at carbon-steel heat. ”

“ A trip through one of the large steel plants with its furnaces, its blooming and slabbing mills, its rail, plate, structural and rod mills is one of the most interesting that can be taken. If the visitor is not afraid of smoke or dust or of what seems to him an uncomfortable heat 276on a warm day he will discover new worlds. No particular attention is paid to the casual visitor to the plant, but, for those who show real interest, steel men have a warm welcome, from manager to the sample boys. ”

“ The technical detail of steel-making is exceedingly interesting to students of applied science, but it is detail, the key to which is in the process mentioned; the forcing of a stream of air through a molten mass of iron. The "converter" is a huge pitcher-shaped vessel, hung upon trunnions so as to be tilted, and it is usual to admit through these trunnions, by means of a continuing pipe, the stream of air. The converters may contain ten tons or more of liquid metal at one time, which mass is converted from iron into steel at one operation. ”

“ So the making of steel was a slow and expensive process until about the middle of the nineteenth century. Then Sir Henry Bessemer, an Englishman, discovered that by forcing air into the bottom of a great retort containing molten iron the oxygen of the air would combine with the carbon of the iron and in a few minutes the objectionable carbon would be all burned out, and that by then reintroducing in this molten mass of pure iron the required amount of carbon in the form of spiegel iron or ferro manganese, steel could be made much more cheaply and quickly than before. ”

“ The principle which regulates the production of steel by these methods is taken advantage of in the Uchatius process, in which pig iron is first granulated by running it while molten into cold water. The granulated metal is then mixed with about twenty per cent, of roasted spathic ore, crushed fine; the mixture, to which a little flux has been added, if necessary, is then fused in clay crucibles. If very soft steel is required, some wrought-iron scrap is added. ”

“ The steels that will harden (we will call them “carbon tool steels”) , range ordinarily from the .60 per cent carbon variety, used for hammers, cold chisels, etc., to those containing 1.50 per cent of carbon which are selected for razors, scalpels, and other tools requiring high temper. Each one of these many grades is susceptible of a wide variety of temper in the hands of a capable man, who must select his steel and give to it the most desirable temper for the work for which the tool is designed. ”

“ A further process is the manufacture of the metal thus treated into SHEAR STEEL, by exposing a fasciculus of the blistered steel rods, with sand scattered over them for the purposes of a flux, to the heat of a wind-furnace until the whole mass becomes of a welding heat, when it is taken from the fire and drawn out under a forge-hammer,—the process of welding being repeated, after which the steel is reduced to the required sizes. ”

“ Our steel industry is thus another triumph of American inventive skill, made possible by the richness of our mineral resources and the racial energy of our people. An elementary scientific discovery introduced the great steel age. Steel, of course, is merely iron which has been refined—freed from certain impurities, such as carbon, sulphur, and phosphorus. We refine our iron and turn it into steel precisely as we refine our sugar and petroleum. ”