Iron plate

“ As none of the constituents except manganese are as 89heavy as iron, their volumes per unit of weight are correspondingly greater. Putting it into approximate figures we have the percentages by weight and by volume shown in Table C.
This means, of course, that of the cast iron plates of your cook stove or steam or water radiators fully one-quarter (26 per cent by volume) is not iron at all but brittle substances of little or no strength. These elements, silicon, sulphur, phosphorus, and carbon, are commonly called “metalloids.” ”

“ Billy looked at him questioningly.
“That was rather technical, wasn’t it, Billy? You see, I was talking to a technical man. Just between you and me, meteoric iron comes down from the sky, from what we call shooting stars. Sometimes large pieces are found. I suppose that much of it falls into the sea. It is the purest iron that has ever been found.”
“What about magnetic iron?” asked Dr. Crandon. “Where does that come from?”
“At the present time,” answered Mr. Prescott, “most of it comes from Sweden and Norway. It makes the best kind of steel. ”

“ Open-hearth iron is practically pure iron, having no constituents or slag inclusions which materially affect its properties.
2. Wrought iron, for all practical purposes, is pure iron 86except for its content of slag. It is the only one of the iron family which does normally contain slag.
3. Neither open-hearth iron nor wrought iron contains carbon in appreciable quantities.
4. The distinguishing and active element of the steel family is carbon. With increase of carbon the hardness of the alloy increases as does its tensile strength, but the ductility (elongation or stretch) decreases. ”

“ With such a volume of weakening constituents and particularly with the graphite flakes cutting through and separating the iron grains as the photomicrographs show, can one wonder that cast iron is fragile—more so than steel or wrought iron? ”

“ It is so highly 75refined that it can hardly be called steel at all but is often called “open-hearth iron” or “ingot iron.” It is probably the purest iron on the market in commercial quantities to-day. While in the chemical laboratory iron of considerably greater purity can be made, for a commercial product this is remarkably pure, seldom containing more than 1⁄4 per cent of elements other than the metal, iron. ”

“ The strength of iron is at its maximum in the smallest mechanical structures.
2. The quality of the metal is improved as it is subjected to greater pressure and condensation.
The extent to which this improvement may be carried has never yet been ascertained; every fresh manipulation improves its quality. The tenacity of wrought iron is best displayed in a wire, drawn out until it is not thicker than a human hair. Large masses of wrought iron are weak and spongy in geometrical progression with the mass, and the crystalline or molecular form increases with the mass. ”

“ While I write, iron is doubtless flowing from blast furnaces in England, Wales, and Scotland; while I write, ingots of white-hot Bessemer steel are being dealt with under the steam-hammer or in the rolling-mills; while I write, horse-shoes are being forged, and, at each moment, in one way or another, pieces of iron of every temperature could be found, from those which are as cold as the iron apparatus used by Sir James Dewar in his experiments in the liquefaction of air, up to the glittering melted steel which is poured from the tilted converter. ”

“ We say that the iron made by the ancients was in reality a variety of what we now term wrought iron, for it fulfilled three of the principal requirements for wrought iron, viz., it was not necessarily melted during production, it was a malleable metal, and it contained cinder or slag, but practically no carbon. ”

“ In the next room he stopped again.
“Different kinds of iron,” he said. “Some much harder than others, like tool steel. Iron cuts iron. That’s a planing machine: automatic plane cuts any thickness.”
Billy stopped beside the mighty planer, moving over the large casting as easily as if the iron had been wood and the fierce chisel only a carpenter’s plane.
They went on a little further, then Mr. Prescott turned suddenly. “William,” he asked, “how long is an inch?” ”

“ Prescott. “Heat expands iron. If we didn’t keep it cool, the screw wouldn’t be the right size when it is done.
“Cold naturally works the other way. Ever hear about the iron bridge where the parts wouldn’t quite come together, so they put ice on to do the job?” he asked, but he kept right on, without waiting for Billy to answer.
Billy saw other machines boring holes and rounding corners. It seemed as if iron could cut iron into any shape that anybody wanted. ”

“ Accordingly native iron which sui generis (as metallurgists term it) , is formed when homogenic parts of the earth grow together into a metallick lode; Loadstone being formed when they are changed into metallick stone, or a lode of the finest iron, or steel: so in other iron lodes the homogenic matter that goes together is somewhat more imperfect; just as many parts of the earth, even the high ground, is homogenic but so much more deformate. Smelted iron is fused and smelted out of homogenic stuffs, and cleaves to the earth more tenaciously than the ores themselves. ”

“ Crandon, “from fishing ore with tongs.”
“We’ve moved along a great way since that time,” said John Bradford, “and most of our progress has been due to iron.”
“Giants don’t do all the work even now,” said Mr. Prescott. “They make short work of iron mountains and surface deposits, but most of them are too large to work underground; though we mustn’t forget that Giant Electricity works down there with the men.
“Giant Gravity helps too, for, when they work below the deposit, he caves the ore down. ”

“ Again, iron which has been excited by a loadstone, * if that iron on account of obstacles should not be able to turn round immediately in accordance with its nature, as happens with a versorium, is laid hold of, when a loadstone approaches, on either side or at either end. Because, just as it can implant, so it can suddenly change the polarity and turn about the formal energies to any part whatever. So variously can iron be transformed when its form is adventitious and has not yet been long resident in the metal. ”

“ A quantity of molten iron should be kept in the cupola or in a large ladle, so as to give the different brands of iron a chance to mix. In most all the foundries at Wheeling, West Virginia, the cupolas are never stopped from the time the blast is put on until the bottom is dropped. A large ladle is set on trestles in front of the cupola, in such a manner that the iron can run into it from the cupola and be poured out into the smaller ladles at the same time. The iron is all run out of the cupola as fast as it is melted, and is mixed in a large ladle. I think this is a good way of mixing iron. ”

“ It is impossible to assign the limits between these three forms of iron, or their relative proportions of carbon, with ultimate precision; for bar iron passes into steel by insensible gradations, and steel and cast iron make such mutual transitions as to render it difficult to define where the former commences, and the latter ceases, to exist. In fact, some steels may be called crude iron, and some cast irons may be reckoned among steels. ”

“ Iron is only prepared on the large scale, and an account of the manufacture would be out of place here. Those requiring detailed information must consult the elaborate works of Percy, Hunt, Fairbairn, Phillips, and other metallurgists.
Pure iron may be prepared by introducing fine iron wire, cut small, 4 parts, and black oxide of iron, 1 part, into a Hessian crucible; covering with a mixture of white sand, lime, and carbonate of potassium (in the proportions used for glass-making) ; and, after applying a closely fitting cover, exposing the crucible to a very high degree of heat. ”

“ But since modern methods of manufacturing have been adopted, tons of metal, which would have been classed as iron if judged by the cooling test, are at present known as mild or soft steel.
Steel may properly be defined as an alloy of iron with carbon, the latter not exceeding 1.8 per cent; the materials are completely fused and poured into molds, allowed to cool, and then rolled into shape. In the processes of making wrought iron the materials are only partly fused and are not cast into molds, but are taken out of the furnace in a soft, pasty condition suitable for immediate working. ”

“ It was only after the next great advance that we found man utilizing iron for his purposes of civilization. This metal, which with us is so common, was in those days very expensive, so much so that it could be used only for purposes of war and as the gifts of kings.
But the world was traveling fast and it was not long before the iron-carbon alloy, steel, was produced. Even so, many hundreds of years elapsed before the present wonderful age was ushered in through the great inventions of Henry Bessemer and the Siemens brothers. ”

“ 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. ”

“ But the difference in the magnetic behaviour of iron and steel is not so well understood, and it is a point of importance for our subject, and connected with a fundamental law which governs all magnetic manifestations. A piece of pure iron is very readily cut with a file, whereas a piece of steel may be so hard that the file 484makes no impression upon it whatever; and hence a piece of pure iron, or rather iron holding no carbon in combination, and possessed of no steely quality, is often spoken of as soft iron. ”

“ It has been repeatedly shown above that iron not excited by a stone turns north and south; further that it has verticity, that is, special and peculiar polar distinctions, just as a loadstone, or iron which has been rubbed upon a loadstone. This indeed seemed to us at first wonderful and incredible; the metal of iron from the mine is smelted in the furnace; it runs out of the furnace, and hardens into a great mass; this mass is divided in great worksteads, and is drawn into iron bars, from which smiths again construct many instruments and necessary pieces of iron-work. ”

“ A brief description of the proper method will still further illustrate the case already considered, and will also show how surface plates are to be corrected.
Take three plates of cast iron, of equal size and proportionate strength. The metal should be of a hard quality. The plates should be well ribbed on the back to prevent them from springing, and each of them should have three projecting points on which to rest, placed triangularly in the most favourable positions for bearing. ”

“ Some kinds are broken up to be used as foundation for roads; others are granulated by being run into water, and so made into cement. Over in Germany, where the ores are rich in phosphorus, they grind up the linings of the furnace to make phosphatic fertilizers for the farmers.”
“Then,” said Dr. Crandon, “the making of iron involves the use of chemistry, doesn’t it?”
“It certainly does,” answered Mr. Prescott; “from the chemical composition of ores to the finished product. We are learning a great deal just now from the chemists about steel alloys. ”

“ During the melting of the charge the heat is kept as high as possible and the molten iron is “puddled,” i. e., stirred, by the “puddler” or his helper with a “rabbler” or iron bar. In order to take out the phosphorus and sulphur, which for best results should be removed before the carbon is eliminated, the heat of the furnace is lowered somewhat as soon as all of the pig has melted, and some iron oxide is mixed into the “bath” of molten iron and cinder. Most of the phosphorus and sulphur are chemically acted upon and pass into the cinder which covers the iron. ”

“ Manufactured irons differ very greatly amongst themselves. For one kind is tenacious in its nature, and this is the best; one is of medium quality: another is brittle, and this is the worst. Sometimes the iron, by reason of the excellency of the ore, is wrought into steel, as to-day in Noricum. From the finest iron, too, well wrought and purged from all dross, or by being plunged in water after heating, there issues what the Greeks call στόμωμα ”

“ In 1854 I took out a patent for puddling iron by means of steam. Many of my readers may not know that cast-iron is converted into malleable iron by the process called puddling. The iron, while in a molten state, is violently stirred and agitated by a stiff iron rod, having its end bent like a hoe or flattened hook, by which every portion of the molten metal is exposed to the oxygen of the air, and the supercharge of carbon which the cast iron contains is thus "burnt out." ”

“ Pure iron is never obtained commercially, the metal always being mixed with various proportions of carbon, silicon, sulphur, phosphorus, and other elements, making it more or less suitable for different purposes. Iron is magnetic to the extent that it is attracted by magnets, but it does not retain magnetism itself, as does steel. Iron forms, with other elements, many important combinations, such as its alloys, oxides, and sulphates. ”