SOME PHYSICAL PKOPERTIES OF NICKEL STEEL. 



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steel, differing as regards the quantity of nickel contained therein, 

 that is so say one has a comparatively small quantity of nickel 

 amounting to from three to eight per cent., according to require- 

 ments, and the other contains a large quantity of nickel amount- 

 ing to twenty-five per cent and more. The former is made of 

 various degrees of hardness, as ingot nickel iron, mild, and medium 

 hard, nickel steel ; the texture is fine and fibrous, not merely in 

 consequence of the nickel it contains, but of the careful and special 

 treatment to which it is subjected while working in a hot state. 



Nickel steel, especially the softer qualities, somewhat resembles 

 the best wrought iron in regard to its fibrous texture, and if any 

 damage is done to its surface such as a crack, or a sharp cut, it 

 will not be rendered liable to sudden fracture like steel, but if 

 subjected to excessive strain it will gradually yield like the best 

 wrought iron. This important property was tested by subjecting 

 axles of nickel and crucible steel to the drop test after first cutting 

 them in the middle by means of a sharp turning tool to a certain 

 depth, thus artificially damaging them. The crucible steel axle 

 was fractured with the first blow falling from a height of 3-3 feet, 

 the fracture being dense, finely granulated and serrated. The 

 nickel steel axle required thirteen blows from heights of 3 3 to 

 21*3 feet to produce fracture, the axle deflecting 7*3 inches and 

 gradually tearing away on the underside of the nick. A hollow 

 nickel steel axle damaged in a similar manner sustained fifty-four 

 blows, of which thirty-four took place from a height of thirty-six 

 feet (that is with a momentum drop of 80,000 foot pounds). 



The figures denoting the strength of the three axles were, after 

 the test, ascertained to be as follows : — 





Tensile Strength 

 per sq. in., pounds. 



Elongation. 

 Per cent. 



Contraction. 

 Per cent. 



Elastic Limit. 

 Pounds. 



1 . Crucible steel axle 



82,800 



208 



57-8 



46,600 



2. Nickel steel axle 



90,900 



22-4 



57-1 



58,800 



3. Hollow nickel steel axle ... 



94,500 



186 



59-7 



65,000 



These results show the characteristic property of nickel steel, 

 namely a high elastic limit. 



