Steed
H. WICKHAM, an English journalist and writer, born in 1871. He was educated at the universities of Jena, Berlin, and Paris. For many years he was acting correspondent of the London "Times" at Berlin, and following this he served in the same capacity in Rome and Vienna. In 1913 he was appointed special editor of the "Times." He made a a specialty sp of Austrian and Balkan affairs and was considered an authority on the subject. He took an active part in the deliberations at the Paris Peace Conference and was consulted on questions relating to Austria-Hungary and the Balkan States. In 1920 he was appointed editor of the London "Times." He wrote "The Socialist and Labour Movement in England, Germany, and France" (1894); "The Hapsburg Monarchy" (1914); "England in the War" (1915); "The English Effort" (1916); "Democratic Britain" (1918).
STEEL. Steel may in a general way be defined as a variety or condition of iron capable of being melted and cast, hammered and welded, and of being tempered, or hardened and softened. It is thus in its properties intermediate between malleable and cast iron, and in its composition it also occupies a middle place between these two varieties. The proportion of carbon contained in the metal is the chief element in determining its character, cast iron containing gen- STEEL erally from 2.5 to about 5 per cent. of carbon, steel having from .05 to 1.80, and the proportion in malleable iron varying from .016 up to about .34; but there are other circumstances which also go to determine the nature and quality of any of the kinds.
The methods by which steel of various qualities is now produced are numerous, but they may all be included under these heads: (1) The partial decarbonization of cast iron; (2) the addition of carbon to malleable iron; and (3) the complete decarbonization of pig iron, and the addition of the necessary carbon by means of pig iron or other kinds rich in carbon to the molten mass. By the first of these processes what are known as natural steel and puddled steel are produced.
Natural steel is made from pure varieties of pig iron (white or fusible gray pig, from spathic or magnetic ores) by melting it with charcoal on the hearth of a refining furnace, as in the corresponding operation in the manufacture of malleable iron; the operation being so controlled that it can be stopped when the desired amount of decarbonization has been effected. Natural steel, known also as Corinthian steel, from having been largely made in that province, formerly in great request on the Continent for tool making. Puddled steel is a similar but less pure product, made also direct from cast iron on the bed of a puddling furnace, the puddling being stopped before the complete oxidation of the carbon. In this process, also, the only difference from the analogous stage in malleable iron manufacture consists in stopping the operation at an earlier stage. The steel of the famous works of Krupp at Essen is made by this process, and it is largely used for machine castings, railway wheel tires, and other large works. was The kinds of steel produced by the imparting of carbon to malleable iron are known as cementation steel, and the varieties included under this head embrace the most valuable classes of steel. The production of cementation steel depends on the fact that when malleable iron is heated to a high temperature in contact with carbonaceous matter with out access of air, it absorbs carbon, and thus becomes converted into steel. Bar ✔ iron of the highest quality only is used for making cementation steel, and the bars are embedded in powdered charcoal and packed in a chamber heated by a a furnace. The temperature is gradually raised, and kept uniformly at a full red heat (about 2,000° F.) for about a week, at the end of which time the furnace is allowed to cool slowly down, which requires another fortnight.
STEEL To make it homogeneous, the bars are faggoted, heated to welding heat, and hammered or rolled, the resulting material being "shear steel." When, instead of being hammered, the blister steel is melted in crucibles and cast in molds, it forms "crucible cast steel," the purest of all varieties of steel, and that which is principally used for files, cutlery, and fine tools generally.
Siemens-Martin steel is produced by what may be regarded as a modification of the cementation process, since in it malleable iron is carburetted by means of pig iron or other compound rich in carbon. On the hearth of an open furnace heated by gas on the regenerative system a quantity of pig iron is melted, and to that scrap iron, old rails, etc., heated to redness, are gradually added.
When by the examination of test pieces it is found that the quantity of carbon is sufficiently reduced, by the addition of malleable iron, for the kind of steel required, the charge is run off. The Siemens-Martin process is also conducted in a manner modified as follows: The pig iron and malleable scrap are melted together, an operation which occupies from two and one-half to three hours, and thereupon a quantity of iron ore (hæmatite) is added to the furnace, which in giving off its combined oxygen decarbonizes the entire charge. When the decarbonization is found to be complete, from 8 to 10 per cent. of spiegeleisen (or about 2 per cent. of ferromanganese), previously raised to a red heat, is thrown into the furnace. After about 10 minutes this will be thoroughly dissolved, the carbon disseminated through the mass, and the charge ready for being tapped off.
Steel so made is now largely used for rails, wagon wheels and axles, and it is being introduced for boilers, ships' plates, and other similar purposes.
Bessemer steel forms the subject of a separate article. Steel presents physical characteristics so distinct from those of malleable iron that it may be for practicable purposes regarded as a distinct metal. Its most remarkable physical characteristic is its power of becoming exceedingly hard by sudden cooling from a high heat, and of passing through many grades of hardness downward from that point by the process of tempering The tempering is accomplished by reheating the metal to a certain degree and allowing it gradually to cool, and according to the heat to which it is raised is the resulting temper, the higher the heat the softer being the steel. Sir Joseph Whitworth introduced a method of compressing with enormous force cast steel in its fluid state, and demonstrated that thereby the tensile strength and homogeneity of STEEL the metal are increased in a remarkable See IRON AND STEEL; BESSEmanner.
MER STEEL.