Page:The American Cyclopædia (1879) Volume XV.djvu/369

 STEEL 357 non-metals. Manganese is closely allied to iron in its chemical properties ; and it plays a very important part, and one in many cases not well understood, in the preparation of steel. Ores containing considerable manganese are often known as steel ores. The beneficial ef- fect of the addition of this metal or its com- pounds in the manufacture of crucible steel was discovered by Heath in England (patented in 1839), but the nature of its action is still some- what obscure. Eecent experiments by Caron show that sulphur is at least in part removed by manganese, and it is also probable that the presence of this metal in the steel prevents the injurious action of sulphur, although as a rule manganese added as oxide in the crucible does not enter into the composition of the steel. The part that it plays in the Bessemer and Martin processes is well understood, viz. : it removes the oxygen that the molten metal has absorbed, and thus corrects red-shortness, and it is probable that its favorable effect may be in many other instances referred to this action. The afiinity of manganese for oxygen is much greater than that of iron, and therefore the re- duction of metallic manganese from its oxide is accomplished with more difficulty; conse- quently a manganese cinder, unlike an iron cinder, protects the carbon of steel from oxi- dation. Further, when manganese is present in molten metal, the oxidation of the iron is prevented until all or nearly all the manganese is oxidized. Below a certain amount, say 1 _>er cent., manganese has been shown, contrary to former opinions, to exert no disturbing ef- fect on the properties of steel. Greiner says that manganese possesses the property of ren- lering steel very malleable and weldable, and that hard steels containing sulphur, phospho- rus, and carbon (as high as T50 per cent.) can be forged with ease if they contain sufficient manganese. Nearly all observers agree that it is a corrective of red-shortness. Manganese steel, so called, was for some time made in Leoben, Austria, but its manufacture was aban- doned, owing to the uncertainty of the prod- uct. The combinations of steel with chromium, tungsten, and titanium have attracted much in- terest from the fact that they appear to have peculiar and valuable properties. They are often represented to be steels in which the metals named replace carbon. This view is inadmissible from a chemical standpoint, and it is probable that these compounds are carbon steels modified in their properties by the pres- ence of other metals. An analysis of Mushet's " special " steel, generally supposed to be made from titaniferous ores, showed the presence of tungsten and no titanium, viz. : tungsten, 7'98 per cent.; carbon, 1 -40; silicon, 0'24. This compound is excessively hard under ordinary conditions; on sudden cooling it breaks, and it can only be worked at a very low red heat. Tungsten has also been added in the Bessemer converter, and the resulting steel, containing as high as 0-558 per cent, of tungsten, was found to combine a high degree of toughness and capacity for hardening. Tungsten likewise in- creases the power of steel to retain magnetism. Titanium seems to produce effects similar to those of tungsten. Chromium also appears to confer valuable properties on steel, somewhat resembling those produced by tungsten. The "chrome steel" manufactured in Brooklyn, N". Y., combines in a high degree tenacity and ductility, and is capable of bearing a high heat for rolling, hammering, and welding. It is highly carburized, one sample giving 0'98 per cent, of carbon, and another 1-23. The amount of chromium found in one analysis was l - 66, and in another it did not exist in appreciable quan- tity. Determinations of the tensile strength of this steel by Kirkaldy of London, on bars 5 in. in length, varied from 115,780 Ibs. to 167,320 Ibs. per square inch, with an elonga- tion in the first instance of 11-6 per cent., and in the second of 7 per cent. Determinations made at the West Point foundery ranged from 173,770 Ibs. to 198,910 Ibs. per square inch. "When hardened at a very low heat, it acquires great hardness ; a high heat renders it brittle, as might be expected from its large percentage of carbon. Copper is sometimes an accidental ingredient in steel. It seems to make it red- short, and its presence even in small amount is believed to be highly deleterious. Faraday and Stoddart have experimented on alloys of steel with the noble metals. They found the compound of steel with a small amount of sil- ver to have valuable properties, but its expense would be a barrier to its introduction. Many analyses of fine steel have shown the presence of aluminum ; and it is not improbable that this metal exerts a favorable action on steel, but the subject has not been investigated. CLASSIFICATION AND MANUFACTUKE OF STEELS. For the purposes of description of steels and the processes of their manufacture, a classifica- tion based on the mode of production may be found convenient. "When iron ore is used, the process is one of deoxidation and subsequent carburization ; with pig iron it is one of decar- burization ; and with wrought iron it is one of carburization. The following outline of pro- cesses is arranged on this plan : 1. Steel from the ore direct, by reduction and carburization. Ore steel, direct steel. Example, bloomary steel. 2. From pig iron by decarburization. a. By solid oxidizing agents, as iron ore, saltpetre, &c., without fusion. Examples, puddled steel, Heaton steel. 5. By solid oxidizing agents with fusion. Example, Uchatius steel. c. By the oxidizing agency of air, with fusion. Exam- ple, Bessemer steel. d. By oxidizing and reducing gases. Example, the Berard process. 3. From wrought iron by carburization. a. By fusion with pig iron. Example. Martin steel. b. By fusion with coal or carbonaceous substances. Ex- ample, Indian steel or wootz. c. By heating in charcoal without fusion. Example, cement steel. d. By heating in carburetted hydrogen, without fusion. Example, Mackintosh or Baron steel. The distinction between crude and fine steel is not now so 'sharply defined as formerly, but in