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is a high grade monthly journal, devoted exclusively to the interests of stationary engineers and to modern power plant practice. It is printed on the best quality of calendared paper, liberally illustrated, and couched in common sense English from which all unnecessary technical formulæ is eliminated. Every stationary and mechanical engineer and every power plant owner should be a regular reader of this excellent journal. The subscription price, if you subscribe now, is

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A BESSEMER CONVERTER IN FULL BLAST, TURNING IRON INTO STEEL.

World Magazine

Volume IV

FEBRUARY, 1906

No. 6

Story of the Steel Industry

Titanic Business which Sets the Pace for Modern Civilization

T

By G. P. BLACKISTON

Iron and Steel Expert

HE giants of to-day-are sons of Tubal Cain. This is the age of steel. From the delicate embroidery needle in the white hand of a woman, to the one hundredton gun, belching forth death to distant battleships, the most important tools of civilization are made of steel.

Far-leaping steel bridges, towering steel sky-scrapers, deep steel tunnels under the earth, steel greyhounds of the ocean, steel engines running more and more swiftly across continents on steel tracks the potent alloy of iron makes. them all possible.

The steel industry has made an almost unbelievable number of millionaires; it is the index to the prosperity of the whole people; it marks also the place of a nation among its peers.

The United States makes more than one-third of the world's production of steel-fifteen millions out of a total of thirty-six and one-half millions of tons; it is the richest and most prosperous among the nations. The two statements are complementary. Germany comes second, with an annual production of 8,000,000 tons; and England third, with 5,000,000 tons.

The 450 steel works scattered throughout the United States represent a total investment of over $442,000,000, and pay $103,000,000 annually in wages. These figures cover only the actual production of steel in its crude form, a process in which man has rapidly been superseded by the marvelous and all but human machines. The magnitude of the industry in its entirety, representing a capital of billions and employing millions of wageearners, may therefore be imagined.

Definition of Steel

Steel is so closely allied, in certain particulars, to cast and wrought iron, that a complete and satisfactory definition of it is almost impossible. Though differing considerably in their physical and chemical properties, they are all alloys of iron and carbon, the essential difference among them being in the percentage of carbon.

Wrought iron usually contains less than 0.30 per cent of carbon, and is not materially susceptible to hardening when suddenly cooled. It invariably contains slag and is malleable. It is the product of the "puddling" furnace.

Steel usually contains between 0.08 and

Copyright, 1906, by The Technical World Company

(661)

2.00 per cent of carbon. Although its minimum limit extends within the bounds of wrought iron, it is free from slag. With but few exceptions, steel is capable of hardening and is malleable at some temperature.

Cast or pig iron contains, as a rule, between 2.00 and 4.00 per cent of carbon, but is not malleable at any temperature.

From these definitions, therefore, it is seen that steel is the alloy between. cast and wrought iron. Various Processes Used

To obtain the physical and chemical properties needed for the numerous and almost totally different uses to which steel is put, several processes are employed in the conversion of of the the iron, scrap, and other raw materials into steel. The most important of these are the "Bessemer," the "open hearth," and the "crucible" processes. The first of these,

selling as high as sixty to eighty cents a pound.

The mixture for melting, consisting of definite and carefully weighed amounts of certain grades of wrought iron, blister bar, alloys, and scrap, according to the grade of steel desired, is packed in pots

MOLTEN IRON BEING POURED FROM THE MIXER INTO LADLES.

It is in this vessel or furnace that the iron is mixed uniformly, previous to being used in the open hearth steel furnaces.

named after its great inventor, the late Sir Henry Bessemer, is the method by which the majority of cheaper steels are manufactured. Accordingly we find the great tonnage of rails, structural shapes, shafting, and the lower grades of sheets and wire, produced in this way. The open hearth process furnishes the steel for springs, shovels, the better grades of wire, forgings, plates, and other articles, in which a higher grade of material than Bessemer is required, yet a grade not so fine as Crucible. When the highest grade of product is desired-such as edge and cutting tools, surgical instruments, razors, saws, die blocks, etc.-steel from the crucible furnace is utilized.

The Crucible Process Crucible steel is made in much smaller quantities than the other forms of steel, the endeavor being to obtain quality rather than quantity. Consequently it is a very high-priced steel, the finer grades

varying in capacity from 50 to 150 pounds. These pots are usually composed of plumbago and German clay, although in England a clay pot is almost altogether used. The life of the plumbago pot varies according to the manner of treatment, the mixture of materials melted within it, and the quality of the pot itself; but on a rough average it might be stated that each can be used three times.

The pots being filled, and a cap placed upon each, they are lifted one by one and placed in the furnace.

Although the crucible process is one of the oldest, but little advance has been made in its operation. The furnaces of to-day and the methods employed, are practically the same as those in vogue during the times of our forefathers in 1789.

The furnace proper consists of numerous holes, varying in number according to the size of the furnace. In Amer

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