SOME PHYSICAL PROPERTIES OF NICKEL STEEL. 151 



Last year an investigation was made on the properties of nickel 

 and iron alloys by Prof. M. Rudeloff, Assistant Director of the 

 Royal Prussian Testing Department, the alloys being melted in 

 small quantities. The results are interesting as showing the 

 influence of varying proportions of nickel on the physical proper- 

 ties of the alloys, and are briefly summarized as follows : — 



Expansion by Heat. — The coefficient of expansion by heat was 

 found to decrease with the increase in the percentage of nickel, 

 but was greater with the 98% nickel alloy than with pure iron, thus 



Pure iron 1-000 



Iron and 4% nickel 0-943 



Iron and 16% nickel 0*891 



Iron and 98°/ nickel 1-091 



Tensile Strength. — The elastic limit, yield point, and ultimate 

 breaking strength increase gradually by the addition of nickel up 

 to 10%, after which a gradual decrease takes place up to 30%. 

 With a further increase of nickel the elastic limit and yield point 

 decrease still more, while the ultimate breaking load increases being 

 greater with 60% than with 30% of nickel. The elongation 

 decreases as the percentage of nickel increases, till at 16% it is 

 almost zero; afterwards it increases up to 60% nickel and then 

 again decreases. The elastic limit, yield point, and elongation of 

 pure nickel are approximately 60% of those of pure iron, the 

 breaking loads being about equal. 



Compressive Strength. — The results obtained in compression are 

 similar to those obtained in tension, but the resistance increases 

 up to 16% nickel, and then decreases. Drop tests. — The results 

 obtained in the drop test show an increase in strength up to with 

 16% nickel, and then a decrease until with 30% nickel it is the 

 same as pure iron. Shearing tests gave similar results to those in 

 tension. 



While the foregoing summary may be taken to indicate relatively 

 the results of varying proportions of nickel, the actual figures 

 obtained in the various tests do not agree with those obtained 



