A RIVAL TO STEEL

Otago Daily Times, Issue 17533, 27 January 1919, Page 2

A RIVAL TO STEEL

MERITS OF ALUMINIDM. Dr W. Kosenhain, in a London address on " Aluminium and its Alloys," said that aluminium alloy was not a German monopoly. A Zeppelin framework had a tensile strength of 25 tons to the square inch, brat this was not so good as the combination of lightness with high strength that could be produced in Great Britain. Comparing steel having a tensile strength of 28 tons to the square inch with pure alinranium of seven tons strength to the square inch, he said that the length, of a vertical bar of steel that could just carry its <ma weight would be 19,000 ft, and of aluminium UjOCOft But with alloy the length of the aluminium bar would b© extended to 50,000 ft. .' . | In large structures like bridges, the weight of the structure was so groat that the weight of a train was almost negligible, but fee point cam© where the span could only just carry itself, and, in comparison with steel, the light alloys of altmiinhrm could increase the limiting span threefold. There was great expenditure of energy in starting and stopping elcotrio trains, and if the heavy steel parts of locomotives could be replaced by light alloys there would b© quicker starting and stopping, /*nd an in> portarrt saving. There was a prejudic© against aluminium, and l the permanenco and stability of the alloys had been, questioned, but research had cleared away doubts. The main consideration that interfered ■with the use of aluminium was that of cost Afcimmrum was extraordinarily plentiful hi the earth's crust, and wo needed a method of extracting' it cheaply. .Cheap olsctricrfcy was essential, and ho looked for this to fee full iitilisation of our water supply.