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Vanadium Steel.*

2nd November 1905
Page 15
Page 15, 2nd November 1905 — Vanadium Steel.*
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It is usual for the president, of an institute, at the opening of a session, to give an address which either takes the form of a review of the industry with which the institute is concerned, or of a speciality in which it is particularly interested. The advantages to me of the latter alternative are considerable, and I therefore propose ti set out in some detail the history and peculiar characteristics of a steel with which I have bad, during the last few years, some experience, and which, owing to these characteristics, is rapidly finding application in motor construction. Vanadium some 20 years ago was a chemical curiosity, and to-day there are not many metallurgists who have seen the pure metal. Sir Henry Roscoe was the first to prepare this, and at that time it was worth many times its weight in. gold. Vanadium is, however, now found to be widely distributed. Its chief deposits occur in South America, Arizona, Spain, and other parts of Europe. It occurs in the iron ores of Luxembourg, and has been found in considerable percentages in the ash of coals, some of which are stated to contain as much as 25 per cent, of vanadic oxide.

The Swedish metallurgist, SefstrOm, in 1832, showed its presence in soft Swedish iron, and the Treberg iron, on which he experimented, was the softest iron then produced, its ductility being remarkable. Mr. J. E. Stead found from o.r68 to 0.262 in four samples of pig-iron examined, the highest percentage being in Cleveland iron. It has also been found in best Staffordshire iron, and especially in the slags accompanying the manufacture of these irons. Notwithstanding the considerable percentage of vanadium in the materials used, the ready oxidizability of vanadium to vanadic acid causes the greater part of the metal to slag off, and it is on this account that the slags from blast furnaces working on vanaditerous materials are so rich in vanadium. Thus, some of the. slags obtained in the smeltings of basic pig in the Luxembourg district contain 2,5 per cent, of vanadium, the pig itself only carrying mots per cent., which percentage is still further reduced or eliminated in its conversion to steel. The slags at the Creusot works in France have for some time been treated for their contents of vanadium, and in 'goo about 90 tons of the oxide are said to have been so obtained. This oxide was entirely used in textile work, on account of the fine black a obtained, and also, to a smaller ex tent, for ink-making, for the same reason. Until quite recently these industries formed the only commercial applications of vanadium, but to show the high value attached to its compounds, it may be mentioned that, in 187*, L32 a pound was offered for ammonium vanadate. The principal source of the metal for metallurgical purposes is vanadinate, which is a mineral containing some ao per cent. of lead, 12.15 per cent, of vanadic oxide, with silica, iron, and some silver forming the other principal constituents, It will be unnecessary for Inc to enter into details as to the various methods employed for obtaining the metal from its ore, I nee-1 only say that the oxide is concentrated from the ore, and this oxide is reduced in the presence of oxide of iron by means of the intense heat of the electric furnace, or by means of aluminium, whose reducing powers are finding such important applications in other departments of technical work.

With aluminium the reduction from the oxide to the metallic form requires a temperature of over 2,000deg., when the evolution of heat from the formation of the alloy is liable, without certain precautions, to give rise to violent explosions, the light given out being comparable to that of the electric arc. Alloys of many other metals, such as chromium, may he obtained by the use of aluminium, and their formations form good lecture experiments, though chronic iron—to which reference will be further made—is obtainable in an ordinary blast furnace, and large quantities rich in chromium are regularly made. In the electric process, the mixtures of oxides and charcoal, and sometimes a little aluminium, are introduced into a plumbago crucible standing on an iron plate, or otherwise electrically connected with the negative pole of a dynamo. A large carbon electrode, forming the positive pole, being balanced by counterweights, is then carefully introduced into the mixture, when an arc is established, and fresh portions of the mixture are added, the operation being watched through a window of claretcoloured and dark green glass. The light is intense, whilst the operation is one requiring much skill and experience.

(To be continued.)

• Presidential address, to the Automobile and Cycle Engineers' Institute, by Mr. Alexander E. Tucker, F.I.C.


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