Steel plate

“ The Rolling of Steel Plates It is manifestly impossible in the space at disposal to give in much detail the rolling of many of the better known products. Fortunately it is not necessary, for after description of the making of plate, pipe and tube, and of rod and wire, the rolling of other forms such as rails, bars, and the structural shapes, I beams, channels, angles, Z bars, etc., can well be imagined. ”

“ When an oblong lump of metal is forced through a series of progressively diminishing apertures in a steel plate, so as to assume in its cross section the form and dimensions of the last hole, and to be augmented in length at the expense of its thickness, it is said to be wire-drawn. The piece of steel called the draw-plate is pierced with a regular gradation of holes, from the largest to the smallest; and the machine for overcoming the lateral adhesion of the metallic particles to one another, is called the draw-bench. ”

“ A plate of steel, with perfectly parallel faces, called a gravity-piece, or feeler, is placed between the flat end of the bar and the standard-piece, and the pressure when the screw-reading is taken must be just sufficient to prevent this piece of steel from slipping down, and that is the case when the steel remains suspended and can nevertheless be easily made to slide about by a touch of the finger. ”

“ Alloy steels of this nature appear to be very susceptible to thermal treatment, by suitable variation of which, with or without oil quenching, the physical condition of the same steel may be made to vary to an extraordinary extent, a peculiarity which is turned to good account in the manufacture of the modern armour plate. ”

“ The plates are prepared for the engraver from sheets of steel about one-sixth of an inch in thickness. A plate cut from a sheet of this kind is first softened by heating it with charcoal, and suffering it to cool gradually in the atmosphere. It is next planished, or hammered on a peculiar kind of anvil, to make it perfectly level, and afterwards ground on one side upon a grindstone. The operation is completed by polishing it with Scotch stone and charcoal. When steel was first substituted for copper, it was hardened before it was used in printing ”

“ Especially when plates are ordered and paid for by average weight per square foot must he judge accurately the thickness of the center of the plate where he cannot measure, and pull down the edges enough 270that the finished plate when sheared will average right.
It is fortunate for the steel mill men of this country which does not know the advantages of the metric system that a steel plate one inch thick weighs very close to 40.8 pounds per square foot. ”

“ In large steel works the greater part of the molten iron is not cast into pigs at all but while yet molten is directly charged into the open-hearth or Bessemer furnaces which convert it at once into steel of which the greater part is made into plate, rails, or other shapes before being allowed to cool. ”

“ Bessemer steel has been largely used for the manufacture of rails, rod, wire, pipe, merchant bar, etc., while open-hearth steel has gone into plate, boiler tubes, structural shapes, billets for axles, etc. ”

“ 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 molten steel as it runs down cleans the face of the wrought iron plate, scoring it in places, and, being of much higher temperature, the excessive heat carbonates the iron to a depth of one-eighth to three-sixteenths of an inch, forming a zone of mild steel between the hard steel and soft iron. The mould is placed in a vertical position to insure closeness of structure and the forcing of gases out of the steel. ”

“ With regard to the metal employed, copper is commonly used, since it is soft and easy to work; its softness however is, in a sense, a disadvantage, since the plate will soon wear, the finest lines being the first to go, so that a limited edition of good impressions only is possible. page 4 To overcome this difficulty, the plate may be faced with steel, by which means it is rendered very durable.
Steel, although once popular, is not much used nowadays owing to its hardness and the rapidity with which it rusts. ”

“ For very thick armour we have therefore adhered to compound plates, employing steel plates where only a few inches are required. France has hitherto produced the best all-steel plates, but a demand for such an article could no doubt be met by our own manufacturers. Already Messrs Vickers have made steel plates which have behaved most satisfactorily under severe tests. Steel is continually being improved, and its resistance to perforation increased by the admixture of small quantities of nickel, manganese, or other substance. ”

“ Great care must be taken not to overheat the plate, and in working, many passes are given the plate with small closings of the rolls. The steel part of a compound plate is usually about one third of the full thickness of the plate.
Forged steel armor, tempered in oil, is fabricated at Le Creusot, France, by Schneider & Co., using open-hearth steel, and forging under the 100 ton hammer. The ingots are cast, with twenty-five per cent. sinking head and are cubical in form. The porter bar is attached to a lug on one side of the ingot. ”

“ Some of the various steel-making plants are equipped for the manufacture of building or "structural" steel, others for rails and railway equipments, still others for tin-plate, or for wire, or for tool steel. ”

“ In one series of the workshops of this same establishment, a considerable manufacture of genuine silver plate is carried on, and it is curious to find mechanics engaged in hammering out or chasing plate, using exactly the same tool that was employed in the fifteenth century, or perhaps in Roman times. No improvement has, or, as it would appear, can be, effected; all superiority now, as then, depending on the workmen.
A great deal of ornamental work, of a stereotype character, is done by stamping instead of chasing. The steel dies for this purpose form a very costly stock in trade. ”

“ A steel containing .19% of carbon and .45% of manganese, for instance, which in one inch plate should give a tensile strength of around 55,000 pounds per square inch, 58,000 pounds in 1⁄2′′ or 62,000 pounds in 1⁄4′′ when finished at usual temperatures, by slightly “colder rolling” can be made to show a considerably greater strength. Of course, the ductility is somewhat reduced, but, with a moderate amount of cold rolling, it will not be enough to do harm. ”

“ It must be cast of hard and close-grained iron, which will possess the most durable qualities, in a baked mold without a cope, so that the gas shall escape most freely. As cast, the plate should be one inch thick. About three eighths of an inch is planed off, [234] removing all dirt, and leaving a perfectly sound surface, with a thickness of about five eighths of an inch. Three of these plates are made. After these have been planed, their edges squared and steel handles put in they are delivered to the fitter. ”

“ In later heavier practice, rolls of cast steel and forged steel are becoming common. They are more costly than iron, but more durable and much lighter for equal strength. They are essential in armour 'plate rolls. The length of rolls should not exceed about four times their diameter, for otherwise they are liable to spring and produce plates thicker at the centre than towards the edges. ”

“ The first is steel made from iron in an advanced state, whether, when made, it be ingots, bars, rails for railroads, sheet, plate, coil, or wire, or hoop-skirt wire, whether covered or uncovered. The second class is car-wheels, thimble-skeins, and pipe-boxes, and springs, tires, and axles, made of steel, used exclusively for vehicles, cars, or locomotives. ”

“ Fig. 1 shows the workman pouring an earthen ladle of molten metal into the molds in which the sole plates are cast. Fig. 2 shows the sole plate in the hands of the workman, held against a rapidly revolving polishing wheel, after it has been run through a milling machine and ground to a perfect size. Fig. 3 shows a huge punch press which cuts the blank of steel that is afterwards drawn to the shape of the iron top. The workman is seen holding in his hand the blank cut from [203] a sheet of steel (Fig. 4) . ”

“ C. L. Siemens and Höpfer of Germany; Prof Sarnstrom and Akerman of Sweden; Turner of Austria; and Holley, Slade, Blair, Jones, Sellers, Clapp, Griffiths and Eames of the United States.
Some of the new metals discovered in the last century have in this century been combined with iron to make harder steel. Thus we have nickel, chromium, and tungsten steel. Processes for hardening steel, as the “Harveyized” steel, have given rise to a contest between “irresistible” projectiles and “impenetrable” armour plate. ”

“ The top part which contains the pipe is cut off and goes back to the furnace to be remelted. It is termed “discard.”
The big steel makers themselves shape most of their steel into such finished products as rails, plates, rods, and wire. Some of it is by them reduced from the ingot into intermediate “blooms,” “billets,” “bars,” etc., and sold in this form for the manufacture of axles, drop forgings and the hundreds of products which we each day see. ”

“ 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. ”

“ 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. ”

“ So, in recent times, researches have been making upon the efficacy of armor plating, no longer in its exaggeration of thickness, but in the intrinsic quality of the metal of which it is composed. Metallurgists have applied themselves to the work and have thus brought out various products, among which the plates called "compound," of Messrs. Cammell & Co., have obtained a great notoriety. These plates, formed of a true plating of steel upon a bed of soft iron, have been much in vogue in the English navy, and seemed as if they were to be adopted about everywhere. ”

“ 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. ”

“ Castings and Forgings.—There are two distinct ways of making the steel objects actually used in the arts, such as rails, gear wheels, guns, beams, &c., out of the molten steel made by the Bessemer, open hearth, or crucible process, or in an electric furnace. The first is by “steel founding,” i.e. casting the steel as a “steel casting” in a mould which has the exact shape of the object to be made, e.g. a gear wheel, and letting it solidify there. The second is by casting it into a large rough block called an “ingot,” and rolling or hammering this out into the desired shape. ”

“ When the carbon has been put in, the retort is closed. The molten metal absorbs the alloy, and the product is Bessemer steel. In fifteen minutes pig iron can be transformed into ingot steel. The invention made possible the use of steel in the construction of bridges, high buildings, and ships. It made this age of the world the Age of Steel. ”

“ I wish to call the attention of the meeting to some of the peculiarities which distinguish cast steel from all other forms of iron, viz., the perfectly homogeneous character of the metal, the entire absence of sand-cracks or flaws, and its greater cohesive force and elasticity, as compared with the blister steel from which it is made,—qualities which it derives solely from its fusion and formation into ingots, all of which properties malleable iron acquires in like manner by its fusion and formation into ingots in the new process ”

“ Often the bolts, clips, nuts, pins, devices and other fittings are of special heat-treated nickel steel which must not be heated locally for bending or for attachment. Such work seriously weakens the steel. ”

“ Of the degrees of heat workmen judge by the change of colour on its surface. Steel, like crude iron, is capable of being melted without losing its properties. It is then called cast steel, and is of a more uniform texture. Iron acquires some little weight by being [Pg 109] converted into steel; and when dissolved in acid, it yields more plumbago. Steel has something less specific gravity than iron. If the cementation be continued too long, the steel acquires a darkish fracture, it is more fusible, and incapable of welding. Steel heated in contact with earthy matters, is reduced to iron. ”