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IV. 



ON THE ELECTRICAL CONDUCTIVITY AND MAGNETIC PERMEABILITY 

 OF VARIOUS ALLOYS OF IRON.* 



By W. F. BAEEETT, F.E.S. ; W. BROWN, B.Sc. ; E. A. HADFIELD, M. Inst. C.E. 



(Plates II.-IX.) 



[Read February 22 (Part I.); May 17 (Part II.), 1899.] 



Introductory. 



The first part of the present paper contains the results of an examination of 

 the electrical conductivity of upwards of one hundred alloys of iron, very many 

 of these alloys being entirely new metallurgical products : the second part con- 

 tains an examination of the magnetic properties of typical specimens of these 

 alloys, complete B and H curves being made in each case. 



In addition to the iron alloys described in the first part, many others were 

 made, but rejected, either owing to the difficulty of getting good castings or the 

 impossibility of forging or rolling the specimens. 



Process of Manufacture. 



For the purpose of the present research, there remained upwai-ds of one 

 hundred different alloys of iron or " steels," which appeared to be fairly 

 homogeneous, and could be forged and rolled. These specimens were rolled into 

 rods of a unifoi'm thickness, and of as small a diameter as could conveniently be 

 obtained. In general the process of manufacture was as follows : — 



Ingots, 2^ inches square, were cast of each alloy ; these ingots were then 

 forged and rolled at a bright red heat (about 900° C) into bars \\ inch diameter. 

 These bars were again heated to 900° C. and rolled into the experimental rods, 

 which were of nearly circular cross-section and approximately 0'2 inch in 



*A joint authorship is given to this paper, as the preparation of the various alloys, and the 

 determination of their chemical composition and mechanical properties were undertaken by Mr. Hadfleld 

 at the Hecla Steel Works, Sheffield, whilst the investigation of the physical properties of these alloys, 

 described in the present paper, was made by myself, and Mr. Brown, at the Eoyal College of Science for 

 Ireland.— W. F. B. 



TRANS. ROY. BUB. SOC, H.S. VOL. VII., PAUT IT. M 



