The New Aluminium.
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Interesting Particulars for the Supply Departments of Motor Manufacturers.
Aluminium ceased to be a metallurgical curiosity some 27 years ago. Disappointment, however, succeeded the glowing expectations of those who first of all. spoke and wrote about it. It retained its lightness, but it failed to meet many requirements in engineering work. Other metals and their alloys progressed in favour and use with engineers : aluminium stood still. Saved by its low specific gravity alone, its relative weakness, brittleness and liability to disintegration owing to fatigue remained inseparable drawbacks to its extended use. Certain promising alloys did not retain their initial characteristics, after a, year or so had elapsed.
We have now pleasure in informing our readers that the new aluminium, which is strictly speaking not an alloy, but aluminium treated with a flux, is about to be exploited under the name of Navaltum, by a company which has been registered with the title of Navaltum, Ltd., and that the registered office of this new concern is Worcester House, Walbrook, E.C., where the fullest particulars may be obtained. Ordinary aluminium is changed into a higher order of its own self. with a result that is comparable to the Bessemer conversion of iron into steel. Its texture, structure and physical properties are changed, whilst its lightness is not impaired ; in fact, in some cases the specific gravity falls. The resultant metal, Navaltum, is found in its cast condition to have a greater strength than the best gun-metal, combined with the ductility of malleable iron ; in its drawn or rolled condition, it possesses a, strength nearly equal to that of mild steel, with all the annealing properties of copper ; it is not corroded by salt water or dilute acids, and it does not tarnish in the atmosphere. These are the claims in support of which protographs which are reproduced herewith have been furnished to us, together with certain test particulars.
Navaltum is found to cast like ordinary aluminium, brass or gunmetal ; no special furnace or precaution is necessary, and the castings have perfectly-clean edges in the fine lines of the moulds. The breaking strain is from 16 tons upwards, and the specific gravity about 2.6.
The metal can be drawn cold, either as bars, angles, tubes or wire, as readily as brass or copper, and with no special precautions, and can be annealed in exactly the same manner. It machines as readily as any other metal, and can be quite easily worked dry. Its remarkable convenience for tooling and manipulation permits sea-water-resisting plates and castings, of Navaltum, to be put together with rivets or screws, also of Navaltum, thus getting rid of electrolytic action. Rivets can be made from it, and the finest-threaded screws can be perfectly cut down to a diameter of one-eighth inch. It can be soldered and welded. It is also thought that it will prove to be an excellent antifriction metal. Tests made on a sheet of Navaltum, rolled down cold from an inch slab, without annealing, to two-thousandths of an inch in thickness, give a test of 16 tons tensile.
We certainly trust that we have at last reached the new aluminium which will fulfil the anticipations and hopes of not only all those who are concerned in its exploitation, but of engineers in many branches of industry, and particularly the various sections of the motor industry.