The American Iron-Master's Work
IN the year 1608 the British East India Company purchased seventeen tons of pig-iron — subsequently declared by Sir Thomas Gates to be “as good as any in Europe ” — for four pounds sterling per ton. This iron had been smelted from ore sent to England by the new colony at Jamestown, Virginia. The successful result of the experiment was not forgotten, although the disastrous speculation in mining and exporting to England glittering mica and iron pyrites for gold drew off the attention of the colonists even from those industries which were necessary to support life; and after its collapse and their narrow escape from starvation there was little heart for mining of any kind. But in 1620 the iron business was begun in earnest, — not, however, in the way of exporting ores. Large transactions of that kind are the product of later times, and peculiar to countries where fuel is scarce. The great need of England at the beginning of the seventeenth century was not iron ore, but fuel. The method of making iron was the most wasteful form of the charcoal manufacture, and had already devastated the forests of a large part of the kingdom. Hence what Evelyn called “the goodly forests of the other world ” offered, in connection with the discoveries of excellent iron ore in Virginia, a promising field for this industry. A hundred and fifty skilled workmen were sent to the colony to erect iron-works, and it is said that a fund subscribed by philanthropic Britons “ for the education of the colonists and Indians” was invested in the enterprise as a means of increasing it. But the copper-colored beneficiaries of the fund, not appreciating these benevolent introductory steps, fell upon the infant institution, massacred all the workmen they could get hold of, and destroyed the works. Various causes prevented the resumption of the undertaking, among them the rapid and profitable development of the culture of tobacco, which became the staple of the colony.
For an interesting review of the progress of the iron manufacture of the colonies, the reader is referred to the recent work of Mr. Pearse,1 who has collected many valuable facts bearing upon the subject. The Centennial address of Mr. Hewitt presents a brief outline of the beginnings of this business and its ante-Revolutionary course, together with a picture of the condition of mining and metallurgy at the close of that period, preparatory to the sketch of the century’s progress 2 and the forecast of the future which form the main portion of the address. Mr. Hewitt covers with his compact but comprehensive generalization the whole field of mining and metallurgy. We are indebted to his address for a few of the following facts concerning the development of the iron manufacture.
Early in the eighteenth century, the blomaries and charcoal blast-furnaces of America began to be seriously felt in competition with the pig-iron manufacture of the mother country. The government having protected by heavy duties the home production, a new competition sprang up in bar-iron, nails, steel, etc., in the manufacture of which the abundant cheap fuel of the colonies continued to give them a decisive advantage. This new difficulty soon overshadowed the old one; and Parliament determined to abandon the pig-iron business to the natural effect of the laws of trade, and to “regulate” the more dangerous industries growing out of it. Hence the famous decree of 1750, by which colonial pig-iron was admitted free of duty, while the erection in America of slitting, rolling, or plating mills, or steel furnaces was prohibited, and all new ones thereafter built were ordered to be suppressed as “nuisances.” It is related that the ingenious mechanics of the colonies evaded this prohibition to some extent by constructing machinery which could be quickly dismantled and hidden. When the visit of a royal official was expected, an active slitting-mill would retire through some convenient trap-door into the cellar, leaving perhaps an innocent grist-mill sole apparent occupant of the building. Only industrious counterfeiters and whisky-distillers labor under such disadvantages nowadays! The Declaration of Independence enumerates these arbitrary acts for the destruction of our infant manufactures among the grievances which justified separation.
The Revolutionary War, while it put an end to American exportation, caused a large demand for iron at home and consequently a rapid increase in its production. Meanwhile, the successful employment of mineral coal, the introduction (1776)of the perfected steam-engine, and the general adoption of the “ puddling ” process completely transformed the conditions of this business in England. When our ports were reopened at the close of the war, our iron industry had to meet, not only the inevitable reaction from its fever of the past few years, but also the competition of foreign iron, now for the first time produced under conditions and by methods which permitted capital to exert its full economical influence. The growth of the American industry from that time to this has been determined partly by the changing tariff legislation, partly by the growing domestic demand, and partly by the successive introduction of various improved methods and machines. The total product of pig-iron (not including charcoal-blooms and other forms of iron made directly from the ore without complete fusion, the amount of which is, however, small in comparison) has been, since 1776, about forty million tons avoirdupois. The maximum product was that of 1873, when 2,560,962 tons were manufactured. That was the year of the panic. But a blast-furnace is not a thing to be stopped in a day, just because of a catastrophe in Wall Street; and either by reason of contracts and orders still pending, or through the influence of a general expectation that the storm would soon blow over, the iron-works of the country kept on at full speed into 1874. But the blow struck them at last, and the history of their business ever since has been one of continued loss and disaster.
Before looking more closely into the present situation and prospects of the iron business, let us devote a few words to the natural resources of the United States in this respect. As we do not purpose to be technical, we shall say as little as possible of the geological, mineralogical, or chemical aspects of the subject. The three great essentials to the profitable manufacture of iron are ore, flux, and fuel, in cheap and regular supply. A fourth necessary condition is cheap and regular transportation to the centres of consumption. But the latter is to some extent furnished by the operation of the former, since the supply of suitable and cheap raw material at any point encourages the growth at that point of industries employing that material. It is cheaper to transport manufactured articles than crude products. Even now, though practically no pig-iron is exported from this country, the annual export of manufactured forms of iron and steel exceeds twenty million dollars in value. This principle operates to create great manufacturing centres, like Pittsburgh, in regions where iron can be economically produced.
Viewed on the large scale, and apart from the temporary phase of the industry supported by the use of charcoal, the iron ores of the United States, it must be confessed, are not conveniently located with respect to its metallurgical fuels. Very brilliant exceptions there are, such as the black-band ores of Ohio; the carbonates, red hematites, and limonites of Western Pennsylvania; the great magnetite deposit of Cornwall, in Lebanon County, Pennsylvania, very near the Schuylkill anthracite coal-field; and some localities in the South which are reported to be highly favored in this regard. At all such points, pig-iron can be and is cheaply produced. Only the cost of getting it to market protects the producers at other points, nearer to certain markets, though further from their own sources of raw material. But the most widely developed and most extensively used of the iron ores of the country are mined in places remote from the coal-fields, such as the Champlain region, or the Highlands of New York and New Jersey, or the peninsula of Michigan, or the heart of Missouri. If we assume that on the average two tons of ore yield in the furnace one ton of iron, while the consumption of fuel is generally from one and one quarter to two tons per ton of iron (less weight of coke than of anthracite being required), it is apparent that so far as these ingredients are concerned the fuel might be carried to the ore not less cheaply, perhaps more cheaply, than the ore to the fuel. This is indeed done at a few points, as, for instance, the blast-furnaces in New Jersey, along the Hudson and on Lake Champlain, and one in Massachusetts, which obtain anthracite from Pennsylvania. But other questions of economy and trade have in most cases settled the relation in the opposite sense; and the great majority of American iron-works are nearer to their fuel than to their ore. Thus the ores of Lake Superior and Missouri find their way to the coal of Indiana, Illinois, Ohio, and Western Pennsylvania, while the great groups of iron-works along the Lehigh draw their supplies of ore largely from the New Jersey mountain ranges. It is not unusual, in fact, to find in their stock-yards material from still more distant lands. Thus there may at almost any time be seen at the Bethlehem Iron Works thousands of tons of Spanish brown hematite, or of the famous ore of Mokta-el-Hadid, in Algiers,— the wonderful deposit which yields more than half a million tons annually, supports a railroad, a sea-port, and fleets of vessels, and supplies all Europe (to say nothing of occasional shipments to other quarters of the world) with perhaps the purest and best “ Bessemer ” ore known. The Spanish ore from Bilbao is also free from deleterious ingredients, but it is not so rich in iron. Under the pressure of hard times and low prices, the somewhat costly business of importing European or African ores to the interior of this country for treatment will probably decline, and Bessemer pig-iron, like other brands, will be made from native ores exclusively. Mokta-el-Hadid has a long arm, but she cannot reach Chicago and Joliet, or even Pittsburgh and Cleveland.
The anthracite furnaces of the Lehigh Valley, the seat of the most extensive manufacture of pig-iron in the country, are between the fuel and the ore, and close by the limestone which they require as a flux. This position is rendered specially favorable by the circumstance that they can draw their supplies from the mountains of the anthracite (Lehigh) field on the one hand, and from the iron ranges of New Jersey on the other hand, by descending grades. During a part of 1876, it is believed that some of these works have obtained coal for less than three dollars per ton delivered, and ores at rates which made the amount of ore required for one ton of iron cost less than nine dollars. Of course these conditions cannot be compared, with exceptional cases, East or West. There are works, for instance, in Alabama, where the item of ore per ton of iron aggregates but ninety cents; the ore in that case being a brown hematite, and lying on the surface, so that to mine it is merely to shovel it. But, on the whole, the commercial importance of the Lehigh Valley may be said to be based on a concurrence of very favorable natural conditions, and therefore to be, so far as the great Eastern markets are concerned, beyond the danger of overthrow for many years to come. The West, however, will no longer be a customer of Eastern Pennsylvania. The decline in the production of the Lehigh, Susquehanna, and Schuylkill valleys since 1872 is partly offset by an increased yield in certain Western districts, particularly the Hanging Rock district in Ohio. The latest development is that of the Hocking Valley in the same State, where many new furnaces have started or are about to start, and where, it is said, with the advantage of cheap coal, ore (carbonate), and limestone, iron is made at a cost of from thirteen dollars to fifteen dollars per ton.
Returning now, for a general survey, to the distribution of the great deposits of iron ores in the United States, we may adopt the words of Councilor Wedding, one of the German commissioners to the late Centennial Exhibition, whose admirable monograph on the American iron industry 3 is now in course of publication abroad. He says: —
“ The great occurrences of iron ore which have a general importance for the industry are confined to the magnetic ores of the eastern crystalline azoic zone, the red hematites and magnetites of Lake Superior, and the similar ores of South Missouri. Great but local importance attaches to the brown hematites of the limestone ranges, the red fossiliferous ores of the Clinton group, and the carbonates and clay ores of Ohio.”
Of the massive but little-developed deposits of the Southern Appalachians, or the Rocky Mountain region (Wyoming, Colorado, New Mexico, Utah), or the Sierra Nevada (California, Oregon), Councilor Wedding says nothing. They form a necessary part of every picture drawn by prophecy of the future industrial progress of the nation; but they are not factors in present problems. The same author estimates the product of iron ores in the United States as follows: —
Eastern Magnetites :
Lake Champlain . 330,000 tons,
New Jersey. . . 620,000 tons,
Cornwall, Pa. . 250,000 tons,
Other districts 100,000 tons,
— 1,300.000 tons,
Eastern brown hematites .... 500,000 tons,
Lake Superior region ...... 1,000,000 tons,
Missouri region . .... 330,000 tons,
All other regions . ... 570,000 tons,
Total . ... 3,700,000 tons,
— representing at sixty per cent. an annual yield of pig-iron of 2,220,000 tons. Since sixty per cent. is higher than the average yield of the ores charged in American furnaces, we must infer that either the ore product is underrated or the iron product is overrated in this statement. It is probable that Councilor Wedding, misled by the absurd traditional confusion of our weights, has taken the amount of ore in gross tons of 2240 pounds, and the iron in net tons of 2000 pounds. For some inscrutable reason, the statistics of the American Iron and Steel Association as to the product of pig-iron are always published in net tons. This is the more unfortunate for foreign readers, because the avoirdupois ton of 2240 pounds is but thirty-five pounds heavier than the tonneau or metric ton familiarly known in Europe, whereas our “ short ” or net ton differs from the tonneau by 205 pounds. Adopting as correct the above estimate of 3,700,000 tons of iron ore as our annual product, and 2,000,000 gross tons as the product of pig-iron, we have an average yield of fifty-four per cent., which is certainly high enough.
It is interesting to observe how our iron mines and mining strike a foreigner familiar with other systems. Councilor Wedding finds a great resemblance between the Champlain deposits and those of Sweden, excepting, of course, the freedom of the ore from phosphorus, in which respect Sweden has the advantage. In the same connection he laments the lack of thorough explorations, which would throw light on obscure questions as to the position and relations of the ore bodies, and says: “ It is a peculiarity of American mining that explorations in advance of actual necessity are practically neglected. Excavation is made from the surface down into the ore, without reference to the labors which will be rendered necessary a few years later; ground is filled with waste rock, which has to be removed afterwards at great cost. This is called a better use of capital, and indeed the calculation of economy in such questions of mining is difficult, since it may easily happen that the developments made do not cover the cost of explorations; but American practice seems to go to an unjustifiable extreme.” This criticism is partially, and only partially, justified by the facts. The greater cost of labor in this country has enforced on the one hand, especially in the mining of cheap ores like those of iron, a system involving as little current “dead work” as possible; but, on the other hand, the same conditions have stimulated the mechanical ingenuity of our people, and the systematic use of the diamond drill (originally a French invention) for “ prospecting ” purposes has been carried on more widely and successfully in the United States than anywhere else. A curious commentary on the condemnation of American mine owners by a German engineer, because they do not sufficiently explore in advance, is furnished by the recent complaint of the San Francisco speculators that the use of the diamond drill in the mines of the Comstock lode has turned “ legitimate ” speculation into a game in which one party has loaded dice. The managers of the mine know beforehand what will be the results of opening each new level or stope, and the purchase and sale of stocks is no longer a “fair gamble.” But aside from explorations for the purpose of ascertaining the limits and value of ore deposits, it is quite true that American mines seldom present large reserves of ground opened in advance with the necessary shafts and galleries, and ready for the systematic extraction of the ore. Hence their history is usually a succession of “ flush times ” and “ hard times” instead of a general average of moderately profitable industry. We cannot pause here to discuss the causes of this fact. They he deeper than any mere whim or peculiarity of national character.
To return to Councilor Wedding: the text from which he preaches seems to be the practice of working iron mines as open cuts and quarries. This is generally admitted to be, except in certain cases (like the hill of iron ore at Cornwall, for instance), poor economy in the long run, because of the ever-increasing amount of “ stripping ” and surface work which it requires, as well as of other difficulties connected with hoisting, drainage, etc. Numerous American iron mines, begun in this way, are now worked subterraneously; but the earlier excavations often turn out annoying and expensive.
The iron-ore deposits of the country are sometimes owned in fee, together with the land, by the parties working the mines; and sometimes the “mineral right ” is leased by the land-owner. In either case the mining operator may be himself a manufacturer of iron, or merely a seller of ore to furnace proprietors. Not infrequently both sources of profit are combined, as at Lake Superior, Cornwall, and Lake Champlain. But in these cases the sales of ore exceed the domestic consumption. A prudent ironmaster would not sell ore that was suitable for his own purposes, unless assured of a supply far beyond his needs for years to come. The leasing of mineral rights has often proved very profitable to the lessor. There is usually a certain royalty to be paid per ton of ore extracted, and a minimum of annual payments fixed in the agreement. A common term is twenty years. Many a plain old farmer, skinning a scanty living from his rocky fields, has come into a handsome income as the result of such a lease. The royalty on iron ores in New Jersey and Pennsylvania has ranged from twenty-five cents to more than a dollar per ton; and the majority of leases now in force probably require the payment of at least fifty cents. These figures were fixed during and after the war, when the high price of iron made the royalty insignificant. They cannot be reduced without the consent of the lessors before the termination of the leases; and they constitute almost the sole item of the cost of iron which has remained unchanged by hard times. The last two years have, however, opened the eyes of mine owners to their true interests; and a voluntary reduction of rents and royalties is gradually coming to pass. Meanwhile, mining operators who own their mines outright are selling ore at prices which scarcely cover the cost of extraction; hundreds of leases have been abandoned; speculators in ore have come to grief; in short, the struggle for life is in full operation, and even the fittest find it not easy to survive.
The main cause of the present condition of the iron industry, in this country at least, is admitted to be over-production. But this is not the whole of it. The 760,000 tons of unsold pig-iron on hand at the end of 1875 and the 675,000 at the end of 1876 do not measure the extent of the difficulty. For these figures show that the iron actually produced in 1875 was all sold. But the American Iron and Steel Association reports seven hundred and fourteen blast-furnaces in the country, with an annual capacity — in round numbers — of five million tons. We have, then, nominally, the power to make five million tons of iron, and
the chance to sell a little over two million. The vast body of idle furnaces is the source of the pressure on the trade. There may be comparatively little steam in a boiler, but all the water is ready to fly into steam if released. In the same way, these furnaces out of blast are ready to start the moment there is a chance or the hope of a chance — nay, even the chance of a hope — of selling iron. More than this: such works represent an enormous capital, at present unprofitable. If it be borrowed capital, the creditors may get the property at a trifling price compared with its cost. If it be the capital of the works, the owners are glad enough to lease the works at rates far below full interest and repairs. In either case, a new operator is enabled to start unburdened with heavy interest charges, perhaps buying ore and coal on credit, and running along “ from hand to mouth,” a dangerous competitor to stable concerns, and a perpetual promoter of forced sales for cash. To meet such competition, some large iron-manufacturing establishments boldly put prices down, and others, after carrying heavy stocks of iron in the hope of improved prices, are at last forced to make sales at a sacrifice. The treatment is heroic, but it is the only cure for the disease. While it lasts, the old established iron manufacturers are in the position of solvent merchants trying to carry on business across the way from a row of bankrupts whom the sheriff or receiver is selling out below cost. When it is over, the bankrupts will be out of the way, and business will begin anew.
This over-capacity of production is not merely the result of a sudden failure in the demand for iron. Two million tons were consumed in 1875, the worst year of the business, and only two and a half million were produced in 1873, its most prolific year. Making due allowance for the fact that in the most prosperous times the actual product must fall short of the total nominal capacity, it is evident that the strong demand for iron in 1871, 1872, and part of 1873 led to an increase of the facilities of production in geometric ratio; and that the disappointment which overtook the trade consisted not merely in a reduction of the actual demand, but still more in the failure of that further increase in consumption which had been confidently expected, and in view of which an enormous amount of capital had been invested in new works or enlargements of old ones. The capital of the iron trade (including rolled and forged as well as pig iron) was reported by the census of 1870 at more than one hundred and two million dollars. It has probably been increased by at least one half since that time, though the general depreciation of values might make, upon an honest inventory of all the property concerned, a different showing. How much of the activity of 187073 and the consequent prosperity of the trade was due to speculation, premature enterprises, etc.; how much was the result of protective tariff legislation; and how much was real and may be expected to return and resume its growth when that vague element known as “confidence” shall be restored are questions upon which we cannot enter here. One thing must be admitted: the prevalence of a similar prostration of this industry in Great Britain and Europe justifies the inference that causes peculiar to this generation rather than this nation have been operating to bring it about. War, railroad extensions, and various speculations “discounting the future” are such causes, and can be traced in other countries than our own. Perhaps it is fair to say that the whole civilized world has been making more iron than was really needed and could be profitably used, and counting too sanguinely upon the continuance of a rate of increase in that demand which was really the product of a sudden “ spurt” of enterprise. Under the stimulus of steam and electricity, many elements of progress have been amazingly accelerated; but one thing, at least, remains old-fashioned, — the way in which people are born, and the rate at which population increases. A simple calculation of the aggregate of population expected to “pour” from somewhere into the regions traversed on both continents by new railroads, which could become profitable only through the settlement of adjoining lands and the growth of business, will show that while a few of these schemes, unincumbered by competition, might have succeeded, most of them were doomed to fail, for one reason, if for no other: people could not be born fast enough to meet the draught upon the supposed surplus of population. It is reported that the managers of one great projected line thought of settling a large part of their lands with Chinese; but, aside from the social and political questions involved in such schemes, the impracticability of suddenly creating a large population in that way is evident. The Chinese have been “ pouring ” into California for many years; yet their numbers are still insignificant.
Another element in the problem of the iron industry all over the world is the growing stock of old iron and the increased facilities for its economical use. The introduction and the enormous extension within the last dozen years of the manufacture of Bessemer and openhearth steel has called for a large supply, not only of new pig-iron, but of pig-iron of specially good quality. The steel rails laid in tracks all over the world have replaced old iron rails, which are everywhere for sale at prices not much above those of pig-iron, and are available for many purposes, though not (in this country, at least) to any extent for the manufacture of steel. The steel rails have a much longer “ life ” than iron ones; and hitherto the proportion of them which has been worn out has been insignificant. But they will begin before long to wear out, and the supply of old material from this source will thereafter be continuous. The two questions, how to utilize old iron rails in the manufacture of steel rails, and how to utilize old steel rails in the manufacture of new ones, are among the most important that now engage the attention of metallurgical engineers.
At the risk of imparting to this article an even more desultory character than its limits and theme involve, we pause to attempt, for the benefit of the nontechnical reader, a succinct explanation of the different processes now in use for the manufacture of iron and steel.
Metallic iron is not found in nature, meteorites and one or two obscure and curious instances excepted. The ores of iron all contain it as an oxide, usually mixed with earthy materials. To reduce the iron to the metallic state, and to separate it from these earthy materials, is the work of the metallurgist. In the blomary or forge this is done by heating the ore in contact with charcoal sufficiently to fuse the earthy material or “ gangue ” with a part of the iron oxide, while another part of the iron gives up its oxygen to the carbon of the charcoal and is reduced to metal. But this metal cannot be melted in the forge; it is too nearly pure iron. It is thus separable from the molten slag, and is removed in white-hot balls and hammered into rough bars or blooms. Hence the name wronghtiron, to distinguish it from cast-iron, which has been melted.
In the blast-furnace the ore is melted in contact not only with coal or coke, but also with such fluxes as may be required to prevent the gangue, when it is fused, from taking up oxide of iron. But in this process the reduced iron absorbs from two to five per cent. of carbon, and the alloy thus formed is fusible. Hence all the contents of the furnace are melted, and the separation of iron from slag or cinder takes place in the hearth, by the action of specific gravity, like the separation of milk from cream, the cinder being the lighter and floating on the top. The liquid iron is drawn from the furnace and run into molds on the floor of the casting-house. As these molds, lying side by side, at right angles to the channels which supply them, have a fanciful resemblance to litters of pigs sucking their maternal parents, the iron ingots are called “ pigs,” and the iron in the lateral channel is called the “ sow.”
Most of the wrought-iron of commerce is made from pig-iron by removing the carbon which it absorbs in fusion. This is done in the puddling furnace, where the pig-iron is melted under exposure to a current of air, and often also in contact with iron oxide. The carbon of the pig-iron acts in the latter case like the charcoal in a blomary forge; it reduces the iron oxide to metallic iron. At the same time all impurities are melted out; the pig-iron, losing its carbon, acquires the infusibility of wrought-iron, and the liquid bath coagulates, or, as the puddlers say, “ the iron comes to nature.” It is collected in balls and removed to be squeezed, hammered, and rolled.
Steel, as formerly understood, was a compound of iron containing more carbon (and possessing greater fusibility) than wrought-iron, and less carbon (with less fusibility) than pig-iron. It could be made by adding carbon to the former, or subtracting it from the latter. The first was the case with the steel produced direct from the ore in forges, and with the manufacture of cemented or “ blister” steel, varieties which, for improvement of their quality, it was usual to remelt in crucibles, whence “crucible caststeel.” Steel has also been made by the fusion of various ingredients in crucibles. The second general method, the decarbonization of cast-iron, was employed in the manufacture of “puddled steel.” The puddling of cast-iron was arrested, so to speak, at an intermediate stage, before the production of wrought-iron, and steel in a pasty condition was obtained.
The Bessemer process consists in the decarbonization of pig-iron by blowing air through it while it is melted. The air burns out the silicon and carbon of the pig-iron, producing so intense a temperature that though wrought-iron is nearly or quite produced there is no coagulation. The metal remains liquid. Theoretically this process, being arrested at any desired point, might be made to furnish any desired quality of steel, or even of wrought-iron. But practically this is too difficult, as a simple illustration will show. If we had more than a pint of water in a pitcher, in which we wished to have exactly a pint, which would be easier: to pour out the surplus, “guessing” when we had a pint left, or to empty the pitcher and then introduce a measured pint? The latter is what is usually done in the Bessemer process. The bath in the “ converter” is decarbonized by the air-blast nearly to the point of wrought-iron. Then a fresh quantity of melted pig-iron, containing a known amount of carbon, is added, to bring the wrought-iron to the desired grade of steel. This last pig-iron, commonly called “spiegeleisen,” contains also a certain proportion of manganese, which (somewhat to the surprise of metallurgists) has turned out to be an essential ingredient, without which the whole process would fail. The most probable explanation of its use is that it unites with oxygen caught in the bath, or with the oxygen of iron oxides produced by the vehement blast and caught in the bath, and otherwise certain to remain in the cast product and to destroy its homogeneity and strength. The manganese uniting with this oxygen carries it into the cinder, which floats on the top of the bath. Another portion of the manganese, however, remains in the bath, and subsequently appears as a constituent of the steel, the quality of which it is held to improve.
The Bessemer process is one of the most picturesque and striking in metallurgy. When first invented, it was recommended as a substitute for other processes (puddling, etc.) which involved much manual labor; and its great capabilities of improvement in respect of mechanical economy have fairly taken the world by surprise. The interior of a large Bessemer establishment like that at Bethlehem, Pennsylvania, is as impressive as a cathedral. The two great converters (or “ pears,” as the Germans call them, in allusion to their shape) are mounted side by side on a platform above the general floor. They swing on trunnions, so that they can turn their mouths upwards to receive a charge, or downwards to discharge it. The cupola furnaces for the preliminary melting of pigiron and spiegel are usually behind the converters and on a still higher level, so that, when tapped, the molten metal may flow through a runner into the mouth of the converter. (This is not the case at Bethlehem, where the melted pig is brought in a huge pot and lifted to the converter.) All the heavy operations are conducted by hydraulic power. Let us ascend, at one side of the great hall, the platform or pulpit where a couple of men stand behind a row of levers, controlling by a touch the movements of the ponderous converters and of huge cranes here and there. The pumping-engines and blowing-engines are out of sight, in another room. This hiding of the causes gives to the effects an appearance of magic.
A “blow” or “heat” is about to commence. One of the converters turns slowly on its axis, until its mouth is on a level with the platform. Immediately a fiery stream of molten iron appears from the obscurity of the recess behind, in which stand the cupola furnaces, and flows rapidly through a movable gutter into the mouth of the vessel. A workman at one side touches a lever, and the converter, which has lain, as it were, on its side to drink in its glowing charge, swings into a vertical position, with its mouth directed towards the throat of a large chimney behind and over it. An instant before, however, a touch upon another lever has caused the monster to begin to roar and to belch a yellowish flame. This is the effect of the combustion of silicon by the blast, which is delivered under a pressure of fifteen to twenty pounds per square inch, through the hollow axis of the vessel, down its side in an exterior pipe, and finally through its perforated bottom into the mass of fluid iron. After five or six minutes, the flame grows white and intolerably brilliant. The carbon is burning, and with so much intense ebullition that particles of melted iron and finely-divided slag are thrown out in showers of sparks. Six minutes more, and a quieter flame, with bluish tinge and still greater heat, indicates the last stage of the conversion. Suddenly the flame shortens with a jerk, as if the monster had drawn in his fiery tongue. With an almost human air of exhaustion after its fit of fury, the converter rolls back upon its belly, to drink, by way of cordial, its final dose of spiegel. This produces a brief internal commotion, but it is soon digested, and the heat is over.
Nothing remains but to pour five tons of liquid steel in a dazzling, almost transparent, incomparably beautiful stream, into the ladle, which delivers it in turn to the ingot-molds. A Bessemer blow is perhaps the most imposing spectacle which metallurgical industry can present. The apparently automatic movements of great masses, the overwhelming display of vehement chemical reactions, and of light and heat in consequence, and finally the rapidity of the whole process, which can be seen from beginning to end in twenty minutes, combine to render it unique as a “ sensational” exhibition. The sudden shortening of the flame at the end of the carbon reaction is so decided that the precise moment of its occurrence may be distinguished from a distance of miles.
Another modern process, the openhearth or Martin process, ally and rival of the Bessemer, is now producing in this country and Europe large quantities of steel. This method consists in decarbonizing pig-iron by melting it in the hearth of a reverberatory furnace with wrought-iron, iron oxide, steel scrap, or iron ore, under the influence, when required, of an oxidizing flame. The decarbonization is carried so far that the bath of molten metal approaches the constitution of wrougbt-iron; and spiegeleisen or ferro-manganese is then added, as in the Bessemer process. It will be seen that the first part of this process, especially when the pig and ore variety of it is employed, involves the same reactions as puddling. But the iron when decarbonized does not “come to nature,” because the temperature of the furnace is so high that even wrought-iron remains fused in it. This sustained high temperature has been made practicable in such metallurgical operations by the invention of Siemens, the regenerative gas-furnace, to describe which would lead us too far from our subject. It is sufficient for our present purpose to note the fact that the Bessemer and the open-hearth steel processes are carried on at temperatures far above those previously maintained in the metallurgy of iron,—temperatures at which all compounds of iron and carbon, from castiron through steel to wrought-iron, will remain in fusion.
It is this circumstance which has led to the agitation, in recent years, of the question now occupying so much of the attention of chemists and steel manufacturers, “ What is steel? ” For besides the alloys of iron and carbon, which contain enough of the latter element (say 0.35 to 1.9 per cent.) and possess enough of the property of “ tempering ” to be called steel under the old definitions, the Bessemer converter and the open-hearth furnace (and to some extent the crucible also) are now sending forth thousands of tons of metal which contains less than the above minimum of carbon, will not practically harden or temper, and yet is not wrought-iron. Convenience and the general practice of manufacturers favor the calling of such metal steel. But the old chemical and half the old physical definition favor its classification as iron. The American Institute of Mining Engineers — a society which, though only five years old, has gathered a large membership, manifested a remarkable scientific activity, and exerted no little influence on the mining and metallurgy of the country — deserves credit for having opened the way to the harmonious settlement of a difference of opinion which threatened to breed confusion in the technical literature of both continents. This society, taking advantage of the presence of numerous distinguished iron-masters from abroad during the late Centennial season, appointed an international committee on the nomenclature of iron and steel; and this committee, representing various views of the question involved and various nationalities (English, French, German, Swedish, and American), presented a unanimous report, recommending a nomenclature which is likely to be adopted hereafter in literature and practice. According to this recommendation, the “low,” “mild,” or “soft” cast-steels will be known as “ingotiron,” the tempering cast-steels as “ ingot-steel,” while iron and steel that are not fused in manufacture will be called “weld-iron ” and “weld-steel;” or perhaps — to retain, without misusing, a more familiar term — " wrought-iron " and “ wrought-steel.” Cast-iron or pigiron remains unaffected by the change. Both parties appear satisfied with this solution, though it still has to pass the ordeal of much discussion; and it may be expected that, for a long time to come, the Bessemer and open-hearth manufacturers will continue to call their products steel, partly because they are, in respect of structure, method of manufacture, and commercial application, fairly cast-steel; and partly because this name indicates to the popular mind and to the trade a more expensive, more uniform, and stronger material than wrought - iron. The best ingot-iron or soft cast-steel is now largely used for boiler-plates, axles, etc., where toughness rather than hardness is the quality required.
There are eleven Bessemer works in the United States, one of which went into operation in 1876, and two in 1875. The product of Bessemer metal in 1875 was 259,700 tons. The product of openhearth steel in the same year was 8080 tons only. But this may be expected to increase rapidly after the present depression of business shall have passed away. A number of the Bessemer works have erected furnaces for the Martin process, in order to utilize their scrap and rail ends. It is anticipated also that this process will have a great future in the remelting of old steel rails, a subject to which allusion was made above. From our description of the Bessemer process, the reader will have perceived that the temperature of fusion is maintained in the converter by the combustion of certain ingredients in the molten bath. But the metal as finally cast into ingots and rolled into rails does not contain enough of these ingredients to support a second combustion of that kind. Hence old Bessemer rails cannot be used, except in small proportions, mixed with fresh pig-iron, in the converter. But the Martin process receives its heat chiefly from the combustion of gaseous fuel, and is therefore available for the remelting of any variety of iron or steel. In bringing to a close this familiar talk rather than formal treatise on the American iron industry, we are well aware that we have given no complete picture of any of its aspects. Our excuse must be — apart from the limitations of space, time, and ability — that it has been our purpose to afford to non-technieal and non-commercial readers a few glimpses into an industry which more, perhaps, than any other is identified with the advancing progress and the increasing complexity of civilization. These innumerable conditions and relations which we have but sketched or hinted at must be studied, comprehended, and handled simultaneously by the managers of great iron-works. One of these large establishments is a world in itself. There are the near or distant mines and quarries supplying the raw material; the railroads and canals, which bring a stendy stream of supplies and carry away a steady stream of manufactured products; the blast-furnaces, which must not stop, day or night; the mighty blowing-engines, the pumps, the pipes, the ovens, all of which must be vigilantly guarded against accidents, which would bring certainly great loss and possibly great disaster; the army of workmen engaged in making or moving materials and products, or in perpetual constructions and repairs; the repair shops, each with its system of machines and necessity of thorough administration. To this must be added the chemical department, whether represented by a regular laboratory and a chemist or by the occasional employment of Scientific assistance. The quality of ores and mixtures and of the products must be ascertained and controlled; the furnaces must be managed, humored, corrected, nursed, like so many willful or ailing children. The workmen and their families are usually tenants as well; and the management, perhaps, complicates matters still further by keeping a store. Finally comes the crowning feat (in these times, at least) of selling the iron, shipping it, and getting paid for it in due time. All this multifarious dealing with human nature, physical laws, and commercial conditions is required for the mere administration of a large establishment manufacturing pig-iron only. But add to that (as is in many instances the case) Bessemer works, Martin steel works, rolling mills, wire mills, nail mills, plate mills, etc., all under one management, and each having its internal economy which must be harmonized with all the rest, and the conception of the powers of the human mind in organizing and directing industry is greatly enlarged.
It is true that in this, as in many other departments, the final impressive aggregate is the result of growlh. Many establishments began small and have gradually increased to their present size. But what shall we say of works like the Edgar Thompson at Pittsburgh, or those at Joliet or North Chicago, which sprang from the brain of the designing engineer, complete in the beauty of symmetry and adaptation! For our part, we must declare our conviction that the original production of such plans, in whole and in detail, by the engineer seems to us an intellectual act partaking of inspiration. The architect of a cathedral, the author of a great poem, do not more distinctly create than do the quiet gentlemen who thus shape in advance the forms and the future of a mighty industry.
R. W. Raymond.
- A Concise History of the Iron Manufacture of the American Colonies up to the Revolution, and of Pennsylvania until the Present Time. By John B. Pearse, A. M., Metallurgist, Engineer, Commissioner of Geological Survey of Pennsylvania, etc. Philadelphia. 1876.↩
- A Century of Mining and Metallurgy in the United States. Centennial Address of Hon. Abram S. Hewitt, President Elect of the American Institute of Mining Engineers, Philadelphia, June 20, 1876↩
- Das Eisenhüttenwesen in den Vereinigteu Staaten von Nord-Amerika. Von Dr. H. Wedding, königl. Bergrath. (Prussian Zeitschrift für das Berg-, Hütten-, und Salinen-Wesen, vol. xxiv. et seqq.)↩