Alexander Lyman Holley
Iron, Steel, Process of Manufacturing, Wootz, Alloys, Damascus Blades, Supposed Methods of Making, Anecdotes, Varieties of Steel
Published Saturday, June 1, 1850 in The American Railroad Journal
Note: I've hand-typed the below words from the original publication as the text, at times, is difficult to decipher and has proven impossible to perform OCR on.
The combining volume of iron is 28, and its specific gravity when hammered 7813. It is the most useful of all metals, and found in abundance in all parts of the world, both in the animal, vegetable, and mineral kingdoms. Though not as highly malleable as silver and gold, it is exceedingly ductile, and may be drawn into wire the thousandth part of an inch in diameter. It is attracted by the magnet, and may be made permanently magnetic in a much greater degree than any other metal.
Iron has in few instances been found in its native state mixed with some earthy substance, copper and lead. Meteoric iron, so called because it was supposed to have fallen from the moon or some heavenly body, has also been obtained alloyed with other metals. Native iron is usually soft, malleable and ductile, not materially differing from that reduced from ores, though it is not as liable to oxidation. Iron is reduced from ores by depriving it of its oxygen by fire. The ores, together with carbon in some form, are subjected to great heat, and the latter having a greater affinity for oxygen, the iron is reduced while the charcoal or the carbon becomes an acid or an oxide, and passes off, or as is commonly said is burned up.
This operation is performed in vast furnaces, the size and working of which is probably familiar to the reader, and therefore need not be described here. The ore and coal together with a portion of fine limestone, which acts as a flux by combining with the clay and forming a fusible compound which runs away below in the form of cinder, are together put in the fire in “charges,” and from two to six or more tons of pig iron made at a casting. Ores, in England, usually contain from 18 to 55 percent of iron, before calcined, or roasted. Carbonic acid and clay, and usually water, sulphur, silex, and perhaps a little arsenic, are ingredients in the composition. The ores are roasted, or as it is generally termed in the country burned, in kilns to free them from impurities, and lose from 20 to 30 percent in weight by this operation. In this country and in England from 2 1/2 to 3 tons of ore, smelted with the charcoal of 3 1/2 cords of wood, or nearly three tons 15 cwt. of bituminous coal will make one ton of pig iron.
Bituminous coal is coked before it is used, which will afterwards be described. A ton of raw coal will produce about 13 or 15 cwt. of coke. Iron smelted by charcoal is particularly adapted to the making of steel, but on account of the expense it is not generally manufactured in England. The texture of iron is fibrous, and is very difficult of fusion, melting at 2754 degrees Fahrenheit, and requiring the greatest heat of a wind furnace. The two principal varieties of cast iron are wisile and gray iron, The former hard and brittle, the latter soft and used for making steel and such castings as required for turning, drilling, and planning. Some varieties of cast iron are purer than others, some containing traces of sulfur, phosphorus, silicum, calcium, manganese, and always carbon and oxide of iron. It is chiefly refined by a process called puddling, which consists in subjecting it to the intense heat of a reverberatory furnace, where as it melts it is gradually worked about, till it becomes less and less susceptible of fusion, and at length grows tenacious and pulverulent.
The mass while stirred emits a bright blue flame aroused by the burning up of some of its impurities. The fire at length agglutinates the metal, which is immediately transferred to rolling mills, or hammered or rolled by machines into balls of different sizes and then passed through the rolling mills, where they are still further purified and formed into bars of different sizes. Both rolled and cast iron are used in the manufacture of cutlery, the former in the shape of nail rods and wire, and the latter for the making of steel and occasionally handles.
Probably the most valuable of all compounds of iron is steel, as it possesses the quality of being hardened and tempered, and is thus particularly adapted to the making of cutlery. Steel is a composition of iron and a small portion of carbon, with a slight admixture of oxide of iron, it is therefore a carburet of iron. The principal varieties of steel, the art of manufacturing which is known, are blistered and cast. The first mentioned kind is made by the process called cementation. a furnace of conical form, with two firebrick cases, capable of containing several tons of iron, is constructed, beneath which is a long grate on which the fuel is placed. On the bottom of the case is placed a layer of pulverized hardwood charcoal, then a layer of wrought bars of pure soft iron, and thus the bars and charcoal dust alternate to the top of the furnace. Flues are also carried through, which are covered with clay to keep the furnace airtight. The whole is kept at a high temperature, usually a red heat, for eight or ten days. The carbon or charcoal is thus gradually absorbed by the iron, probably in a gaseous state. It has not been certainly ascertained whether the union of the carbon with the iron is chemical or mechanical, but it is supposed by some to be both, for the reason that the damasked surface of some of the celebrated sword blades is owing partly to a chemical and partly to a mechanical union. But this appearance may be caused by chemical changes alone, acting partially on the original carburet and depositing carbon unequally. This steel is blistered by the escape of the air and gas from the interior and hence its name. Toward the end of the process, constant and careful watching is necessary, or by the absorption of too much carbon the bars may suddenly be fused.
The progress of cementation is discovered by withdrawing and breaking a bar, called the “test bar,” which must be colored alike in the centre and at the surface. When the steel is completely made the fire is extinguished and the furnace left to cool, which takes from six to eight days. These bars are repeatedly broken, welded and drawn out, till the specific gravity and fineness are increased, and great care is taken during the operation, to preserve the surface from oxidation.
Steel to be benefitted by hammering should be heated to a temperature neither too hot nor too cold, for in the first instance only the shape is changed, and in the last the particles are dislocated and scaled off, but at a low cherry red the metal is condensed and thus made better. There are two methods of making cast steel. The following is the receipt of an old English steel manufacturer, viz: “Re-melt blistered steel of a proper hardness in crucibles, together with a handful of fine charcoal and 2 ozs. Of manganese to every 28 lbs. Of metal; cast into ingots and weld and draw out until it is sufficiently fine.” The other method is by melting soft iron (Swedish and Russian are the best in use) with powdered charcoal, and a flux of vitreous and carbonaceous substances in a large crucible placed in a wind furnace. When the fusion is complete, it is cast into small bars or ingots, which are subjected to the same process of repeated welding through which are passed the bundles of blistered steel. Cast steel is harder and more elastic, it receives a higher polish, and has a much closer texture than common blistered steel.
Another mode of applying carbon is by a stream of gas, but this is not in general use. The most skillful manipulation is requisite as the point of sufficient fusion is reached, and it must be performed under severe exposure to the most intense heat.
Wootz, a cast steel from India, has been very successfully employed in the manufacture of cutlery in England which the experiments of Messrs. Stodart and Faraday have shown to be an alloy of steel with small quantities of silicium and aluminum. Wootz is made by placing alternate layers of wood and malleable iron in a furnace somewhat resembling our furnaces for cementation, and converted into steel in the same manner that common blistered steel is made. It is then fused and crystalises in the crucibles, in which state it is imported. When remelted and passed through the same operations to which our steel is subjected, it is superior to all known steel. Some have attributed its peculiar virtue to its cementation being performed with wood, but it is evidently made from iron reduced from very superior ores, or owes its excellence to its being alloyed with other metals. Great care is necessary, or it is easily ruined when fused a second time.
Numerous alloys of steel have been made, among the most useful of which is a compound of 500 parts steel to one of silver. If a larger proportion of silver is used it does not smoothly and evenly combine with the steel. The alloy of steel with 100 parts of platinum, though less hard, is more tough than the above compound, therefore very valuable, combining tenacity and hardness. Steel alloyed with rhodium exceeds the two former in hardness, and compounded with osmium, palladium, and iridium, is also excessively hard, but on account of the rarity and expense of these metals, it cannot be successfully applied to practical purposes. A compound of gold and steel, is also of great utility in some cases.
As before mentioned, iron produced from meteors is less susceptible of oxidation than any other, probably owing to its combination with nickel. Perhaps an ally made by combining these two metals might be highly valuable. The art of making steel held to be similar to the Damascus sword blade, is now lost and was perhaps never thoroughly understood in Europe, though various explanations have been given in regard to the character and structure of these celebrated weapons. They were never known to break in battle, and always retained an edge sufficiently hard and powerful to cut through helmets, armor, and all impediments. It has been supposed, on account of their striated appearance, that they were formed by extremely thin sheets of iron and steel wound with fine soft iron wire, and welded firmly together. Some believe that they were made by winding ingots of hard steel alone with tenacious iron fiber and cementing them at great heat, while it is thought by others that they were the product of fine iron converted into steel by the carbonic acid gas, into which diamonds turn when burned up, these being the purest carbon known. But this theory is incorrect, from the fact that diamonds were first burned by Florentine Acadeicius in the year 1649, and the products of this burning were first examined by Lavoisier in 1779, long after the Crusades, when Damascus blades were in use. Many persons are confident that this meta was an ally of gold and steel, and others that it was a compound of silver and steel, the chemical and mechanical unions together causing the damasked appearance, while others affirm that they were alloys of either platinum and steel, and thus both ard and tenacious, or of palladium, osmium, or some similar metal, with iron or silver and steel. Perhaps the most probable method of constructing these blades, was by the repeated and continued hammering of hard steel of a superior quality, and soft very tough iron fiber, running in all directions, at a cherry red, till the fineness and specific gravity were greatly increased, the steel holding the edge and doing the execution, and the fibers of iron, by virtue of their tenacity, binding the whole together, and preventing its breaking.
Many anecdotes are related in regard to the wonderful powers of these and other swords, which, though we cannot listen to them with unshaken credulity, are perhaps based on truth. One only will be mentioned. Two celebrated warriors were testing the virtues of their swords. The first commanded a thick bar of iron to be laid on the block, which he cut asunder by one tremendous blow of his double handed broad sword, without breaking, bending, or injuring its edge! The other one then called for a quantity of down, which he blew upward, and as it slowly fell it was cut in two by one stroke of his cemetery. Someone has added the following supplement to this story, which though highly interesting, is hardly credible. The first general not being satisfied, the latter ordered an attendant to come forward, across whose neck he drew the back of his sword, and asked, “Did you feel that?” The servant shook his head. He then drew the edge across his throat, asking the same question. As the victim attempted to reply by the former sign his head dropped into his hands!
Steel is used for the manufacture of an almost innumerable variety of blades, which are designed for numerous and entirely different operations, and therefore various degrees of tenacity and hardness are required. The steel of a lancet must necessarily be hard and susceptible of a fine edge, being used for purposes that require the exact and perfect operations, consequently very brittle, while the same metal in the form of a trowel, exceedingly tenacious, or it will break in trimming bricks, but the fine edge is not at all necessary.
Probably almost every cutting instrument has some property peculiar to itself. Pen, and the smaller varieties of pocket blades, should be hard and very fine grained, while the larger kinds should be a little more tenacious, though their thickness will usually prevent their breaking by hard usage. Both cast and blistered steel are in constant use in the manufacture of knives, the former for blades and tools, and often for backs, springs, and other fine work, and the latter almost wholly for springs, though occasionally for handles, implements and machinery.
To be continued.