154 



W. H. WARREN AND S. H. BARRACLOUGH. 



In regard to nickel steel containing 25% of nickel and more. — 

 This material has been proposed for those parts of engines and 

 machinery which are specially liable to rust; it possesses great 

 strength and ductility, but has a somewhat low limit of elasticity 

 hence it is not so suitable for parts liable to great strains. It has 

 been proposed for the construction of locomotive fire boxes, for 

 which purpose it appears to be eminently suitable. 



4. Nickel Steel from the Bethlehem Iron Works. — In the Beth- 

 lehem Iron Works, U.S.A., nickel steel forgings are made from 

 fluid compressed, acid open-hearth steel, and are carefully annealed 

 after forging. To get the best results it is necessary to use an 

 ingot twice the diameter of the finished forging to be made from 

 it, in order that the proper amount of work shall enter into the 

 metal during the time of its reduction in size under the press. 

 The ingot also should have from 30 to 50% extra metal at the top 

 which is cut off, as only the lower portion of the ingot is solid and 

 suitable for forging purposes. Whenever the form and size of the 

 forgings will allow of such treatment, they should be made hollow 

 by boring, and they may also be oil tempered. Presses should 

 always be used in preference to hammers, and should produce a 

 pressure penetrating to the centre and causing a flow throughout 

 the mass. 



The steel used in the field magnet rings of the large Niagara 

 electric generators was made at the Bethlehem works. Each 

 ring was forged in one piece without welding, from an ingot of 

 nickel steel, 54 inches in diameter and 197 inches long. The ingot 

 was cast solid and compressed by hydraulic pressure in the fluid 

 state and during solidification. A hole was bored in the ingot 

 which was subsequently expanded on a mandrel under a 14,000 

 ton hydraulic forging press. The material was tested after forg- 

 ing to obtain the physical qualities desired, the results being as 

 follows : — 



Sample No. 



Tensile Strength 

 pounds per sq. in. 



Elastic Limit, 

 pounds per sq. in. 



Elongation on two 

 inches, per cent. 



1 



82,915 



53,560 



2705 



2 



81,110 



47,230 



25-75 



3 



82,140 



49,280 



22-50 



Average 



82,055 



50,023 



2510 



