The Pittsburgh reduction co. manufacturers of aluminum and aluminum alloys in the form of ingots, castings and all forms of structural shapes - Softcover

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1904 Excerpt: ... The production of smoother surfaced castings and ingots of steel than it is possible to obtain without the use of aluminum. There are no such metals as "aluminum steels," in the same way that there are "nickel steels" and "chromium steels." Aluminum is not a hardener of steel, and none of its alloys with steel in material proportions have so far proven advantageous. It has been proved that the addition of aluminum to the steel just before " teeming " causes the metal to lie quiet, and give off no appreciable quantity of gases, producing ingots with much sounder tops. There are two theories to account for this: one, that the aluminum decomposes these gases, and absorbs the oxygen contained in them; the other is that aluminum greatly increases the solubility in the steel of the gases which are usually given off at the moment of setting, thus forming blow-holes and bubbles. Probably both of these causes operate to produce the desired effect, but the well known affinity of aluminum for oxygen would point to the former as being the chief action, i, e.t in combining with both the carbonic oxide and the dissolved oxide of iron which may be present. Professor Arnold has shown that blowholes in steel and iron are partly caused by the presence of carbonic oxide gas in the metal, and this gas is decomposed by the aluminum which unites with the oxygen, forming alumina, or oxide of aluminum, setting free the carbon, which appears as uncombined carbon or graphite. It also combines, in some way not yet determined, with the hydrogen and nitrogen present, absorbing these gases or rendering them more soluble in the steel. Aluminum also sets free much of the remaining carbon in the steel, as the following result obtained by Mr. R. A. H...