Metallurgy

“ In metallurgic works the first thing is to break the mixed ore into small pieces, in order to separate the valuable from the useless parts, by processes called stamping, picking, sorting. See Metallurgy and Mines. ”

“ In really successful mining it is in the last degree important that the mode of extraction of metals in the most scientific manner should be thoroughly understood, but as a general rule the science of metallurgy is but very superficially grasped even by those whose special business it is to treat ore bodies in order to extract their metalliferous contents, and whether in quartz crushing mill, lixiviating, or smelting works there is much left to be desired in the method of treating our ores. ”

“ The property which every substance has of sinking through a fluid of less density than its own forms the basis upon which nine-tenths of the gold and copper, and probably six-tenths of the silver produced in this country, is extracted from its ores. It is the foundation of the art of ore dressing, one of the most important parts of metallurgy. ”

“ The open-hearth process of steel-making consists in making pig iron mixed with a greater or less quantity of wrought iron, steel, or similar iron products by exposure to the direct action of flame in a regenerative gas-furnace, and converting the resultant bath into fluid steel. Like the Bessemer process, the open-hearth process is divided into an acid process and a basic process; in the first the hearth is lined with sand and the slag is siliceous, and in the second the hearth is lined with a basic material and the slag is basic. ”

“ A knowledge of the mixture of copper, tin, and zinc, seems to have been among the first discoveries of the metallurgist. Instruments fabricated from these alloys, recommended by the use of ages, the perfection of the art, the splendour and polish of their surfaces, not easily injured by time and weather, would not soon be superseded by the invention of simple iron, inferior in edge and polish, at all times easily injured by rust, and in the early stages of its manufacture converted with difficulty into forms that required proportion or elegance."— (Papers on Iron and Steel, 365-6.) ”

“ The arrangement adopted with these is first to show the ores from each district, next the mode of smelting those ores, the metal procured, and generally the manufacture of the metal. The Iron, of course, assumes the first importance. The Pig Iron is the first state in which the metal is obtained; it is then submitted to the refining and “puddling” processes; then rolled into bars, nails, and plates, or drawn into wire; we then see it converted into steel, by various processes including Bessemer’s, and this leads us to the manufactures of Sheffield. ”

“ The mineral is treated, and the crude metal, which is of greater value, is obtained. The crude metal is refined, and iron is got, which is better. The iron is treated, and, by cementation, it is converted into steel. The steel is wrought, and a thousand things directly useful to man are produced.
The utility of these last products increases in a direct ratio to the amount of labor which men have expended. An anvil weighing a thousand pounds is less useful than a thousand wrought files; it costs less labor. ”

“ At length, after many trials and much fatigue, on the 25th of April several bars of iron were forged, and transformed into tools, crowbars, pincers, pickaxes, spades, etc., which Pencroft and Neb declared to be real jewels. But the metal was not yet in its most serviceable state, that is, of steel. Now steel is a combination of iron and coal, which is extracted, either from the liquid ore, by taking from it the excess of coal, or from the iron by adding to it the coal which was wanting. ”

“ Power Presses in Metal Working.
From glass let us now turn to metals. It is their tenacity that chiefly gives them value; this tenacity is usually accompanied by a hardness which disposes us to regard nickel, for example, as of a solidity quite unyielding. But the coins in our pockets prove that under the pressure of minting machinery they are as impressible as wax. In molds and dies, each the counterpart of the other, brass, bronze, iron, steel, and tin-plate take desired forms as readily as if paste. Solid though these metals appear they yield under severe stress with a semi-fluid quality. ”

“ Returning to the eleven well-known true metals, viz., aluminum, copper, gold, iron, lead, mercury, nickel, platinum, silver, tin and zinc, wonderful progress has been made during recent years in the matter of their production. Few of us appreciate the extent to which we are absolutely dependent on some of these substances which, a generation ago, were so rare. It is quite impossible now to conceive of a metal-less civilization, or one in which they were so costly as to be practically unavailable for the ordinary affairs and circumstances of life. ”

“ Besides two huge furnaces for smelting the raw ore, there are upwards of thirty others for the washing, puddling, and treatment of the iron in its various stages; eighty forges, two iron founderies, and one of copper; one vast hall for the construction of boilers, another for fly-wheels, and all the portions of steam-engines, and a third for locomotives; [180] besides innumerable apartments for every other species of heavy machinery, rooms for designers and magazines of models. (The spinning, and other light machinery, is manufactured at another establishment at Liege.) ”

“ Every department of human industry is represented, from the quarrying and the cutting of the stones, the mining and smelting of the ores, the conversion of iron into steel by the pneumatic process, to the final shaping of the masses of metal into useful forms, and its reduction into wire, so as to develop in the highest degree the tensile strength which fits it for the work of suspension. Every tool which the ingenuity of man has invented has somewhere, in some special detail, contributed its share in the accomplishment of the final result. ”

“ We forget that, with primitive methods but fine ores and a fuel devoid of sulphur, the production of steel of fine quality is as easy a process as the manufacture of iron, in fact the only difference between the method of procuring iron and steel under these circumstances is the length of time the process is allowed to go on. The ancient founders used the finest ores, often containing 75 per cent. of iron, and, working with charcoal fuel, which was nearly pure carbon, they could produce steel as easily as iron. ”

“ This refutation is to be seen in our blast furnaces, refining furnaces, puddling furnaces, Bessemer ladles, steel melting-pots, cupels, foundry crucibles; in fact, in almost every metallurgical operation down to the simple fusion of lead or solder in a plumber’s ladle, with its familiar floating crust of dross or oxide.
As an example I will, on account of its simplicity, take the open hearth finery and the refining of pig-iron. Here a metallic mixture of iron, silicon, carbon, sulphur, etc., is simply fused and exposed to the superficial action of atmospheric air. ”

“ Thus, when combined with carbon, in varying proportions, substances are produced, so different, but each so valuable, that they might almost be regarded in the light of distinct metals,—such, for example, as cast-iron, and cast and bar steel; the various qualities of iron enabling it to be used for purposes so opposite as a steel pen and a railroad, the needle of a mariner's compass and an Armstrong gun, a surgeon's lancet and a steam engine, the mainspring of a watch and an iron ship, a pair of scissors and a Nasmyth hammer, a lady's earrings and a tubular bridge. ”

“ Containing, as it does, a larger percentage of iron than any other source from which the metal is commercially extracted, its employment as an ore results in great economy of fuel, as well as a reduction in the proportionate costs of transport. When ores of iron require [Pg 190] to be brought from oversea places, it is obvious that those which will concentrate to the purest product possible, and which are in other respects specially applicable to the production of grades of steel of exceptional tensile strength, will have the preference. ”

“ Railways were stretching their lines into the golden regions of the West; manufacturers of farm implements were calling for steel to be fashioned into tools to reap the rich crops of the wide prairie lands; inventors were each day evolving some new use for the metal. Was it any wonder then that steel became a world necessity and that the blast furnace became a philosopher’s stone that transmuted dull ore into precious gold? ”

“ Metals Used in Hardware Manufacture.—The metals chiefly used in manufacturing the products of the smiths’ art are iron and steel and the copper alloys known as brass and bronze. Iron remains as the chief material of construction for all the cheaper grades of hardware, while brass and bronze are more generally used for “destructible,” or wearing, parts and the finer and more elaborate decorative work. ”

“ Too, the metal for valves and fittings and other more or less complicated castings for high steam, air, ammonia, water, etc., must be uniform, of close grain, strong, yet soft enough to machine easily at the extremely high speeds which modern efficient tools and methods demand. The production of the best metal for such work requires the use of properly selected materials, judicious mixing, and clever operation of the cupola furnace, that the molten metal delivered to the foundry for the pouring of the molds may be hot and fluid and of the right composition for the particular work in hand. ”

“ 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. ”

“ Iron and steel and their alloys are the most generally used of the metals. The raw materials necessary for their manufacture include a wide variety of minerals.
Iron is the principal element in this group; but in the manufacture of iron and steel, manganese, chromium, nickel, tungsten, molybdenum, vanadium, zirconium, titanium, aluminum, uranium, magnesium, fluorine, silicon, and other substances play important parts, either as accessories in the furnace reactions or as ingredients introduced to give certain qualities to the products. ”

“ It is worthy of remark, that the ruder the method employed for the reduction of the ore, the better the quality of the iron usually is. Where the art is little advanced, only the most tractable ores are selected; and as charcoal is the only fuel used, the quality of the metal is almost invariably excellent. The ore being long exposed to the charcoal fire, and the quantity made small, the result is a metal having many of the qualities of steel, capable of being used for weapons or tools after a comparatively small amount of forging. ”

“ 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. ”

“ This metal can be reduced by forging to any shape; but, during the process, it will bear no heat greater than a red heat; and, as it does not admit of welding, like iron, different pieces are united with bolts, or rivets, of the same metal, as in the case of the larger kinds of vessels, or by means of solder made of brass and zinc, or zinc and lead, as in the case of those of smaller dimensions.
5. Brass is applied to a greater variety of purposes in the arts than copper. ”

“ 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. ”

“ Your progenitors learned to dig the hard and soft ores from the earth and produce iron, then took a step forward and converted it into steel, of greater strength and durability, capable of light forms and high polish, and there you have stopped at the very beginning. You [84] are incapable of saving your own handiwork from disintegration. The elements corrode your finest steel products, and they flake away to the original conditions of the crude ore, losing a large proportion of their original virtues and constituents. We have, on the contrary, gone forward to the ultimate. ”

“ Between these rolls, which are placed horizontally, and form a tank or channel when they approach each other, the molten metal is poured, and thus a sheet of any desired width or thickness may be formed, and only limited in length by the supply which the crucibles are capable of keeping up. The ore goes into the furnace a crude stone, and comes out of the rolls a sheet of tough metal. Iron-making is thus rendered as simple as the paper-making processes, where the rags go in at one end of the train of apparatus, and come out at the other perfect paper. ”