STEEL SUBSTITUTE

Te Awamutu Courier, Volume 59, Issue 4222, 11 December 1939, Page 2

STEEL SUBSTITUTE

NEW METAL PRODUCED PROPERTIES OF NAVALIUM. A new light alloy metal, a substitute for steel, which may cause a revolution in ship biulding, was discussed by the Institution of Naval Architests last month. It is called navalium, and it is made of aluminium and magnesium. x Mr W. C. Devereaux, who has had wide experience of aluminium alloys in aircraft construction, and Mr E. V. Telfer, a scientist member of the Council of Naval Architects, presented a paper in which they discussed the possibilities of the new metal as a substitute for steel. They announced that the aluminium industry will finance a research scholarship of the value of £250 a year for young naval architects in order that problems arising out of the use of navalium in shipyards may be fully investigated. There are at present six forms of navalium suitable for ship building, they said, but as time proceeds even fewer will suffice. It can be produced In plates one inch thick, and in ang les, Z bars, girder sections and channels up to 85 feet in length. It can be riveted or welded. The factor of weight saving ranges from “3” in low speed warships to “6” in destroyers, and no particular problem affecting safety appears to be presented. The principles of armour design, however, would require earnest reconsideration. Indent damage to the plating should be less likely than in steel, owing to the much greater elastic deflection of the light alloy. The authors instanced experience with milk churns made of navalium, where with deliberate misuse surprisingly little damage has been found, much less than thal, usually sustained with steel churns. Regarding ship design with the new metal, the authors said that increased stream lining would of course be Inevitable, but of far greater importance was the possible return to aulxliary light alloy sails. The masts and funnel would be replaced by streamlined structures, consisting of a mainsail, an adjustable tail flap, a rotor nose in association with a nose stop of the Handley-Paige type, or, more nauticaHy expressed, simply a jib. Such sails would prevent the wind causing a wasteful resistance which had to be overcome and would be auxiliary power to the main engines. Corrosion resistance of navaliurii could be shown to be much superior to mild steel. Recent tests, quoted in the paper, went to show that the corrosion of steel was five times as rapid as that of the navalium alloy. It required to be covered with aluminium paint. Solution of the problem of fouling of the under-water hull was still outstanding. Increased production in. the heavier units required for ship building, it was contended, would produce in a few years substantial reductions in the price of navalium. The halving of the present ingot prices at least was reasonably to be expected. If navalium cost three times as much as steel, structural savings in the cost of building would still be enormous. In warships they calculated that one ton of navalium could save eight tons in structural and machinery weights, as well as producing a power and fuel reduction on account of the smaller size of the vessel for a given duty.