[Proc. Roy. Soc. Victoria, 23 (N.S.), Pt. IL, 1911.] 



Akt. XXVII. — TJic Magnetic Properties of Stallo>j. 

 By H. R. HAMLEY, M.A., 



AND 



A. L. ROSSITER, B.Sc. 



(Government Kesearch Scholars, University of Melbourne). 



(With Plates LXII.-LXV.). 



[Read November 10th, 1910]. 



(Communicated by Professor T. R. Lyle). 



In the following paper are given the results of an investigar 

 tion into the magnetic properties of the iron alloy called 

 " Stalloy." Particular attention has been given to " Stalloy " 

 by many investigators on account of the claims made by its 

 inventor (Hadfield) with regard to its magnetic properties. The 

 special feature of this alloy is its high specific electric resist- 

 ance and high permeability. The specific resistance being 

 about four times that of the best transformer iron, the eddy- 

 current loss for a given thickness of sheet would be greatly 

 reduced, so that lamination need not be carried out to anything 

 like the extent necessary with ordinary iron, and the question 

 of insulation of laminae becomes less troublesome. It is more 

 expensive than ordinary iron, but the increased expense is com- 

 pensated by a reduction in size oi the transformers etc., con- 

 structed of it, an increase in output, and greatly improved 

 efliciency. 



The special chemical feature of " Stalloy "' is that it con- 

 tains about 3.4 per cent. Silicon. The value of this alloy is 

 emphasised in a paper by Epsteini, where several tests of its 

 properties are given. 



Several investigations liave been made by other experimenters 

 by direct current methods, which agree fairly well together. 



1 Epstein. J.I.E.E., vol. xxxvi., 1907. Professor Turner gives the analysis as follows : 

 Carbon .03, Silicon 3.4, Sulphur .04, Phosphorus .01, Manganese .32, Iron 96.20 per cent. 



