SOME PHYSICAL PROPEKTIES OF NICKEL STEEL. 



157 



tests of Yicker's axle-steel made with Kennedy's extensometer 

 gave an elastic limit of sixteen tons per squre inch, whereas the 

 Marten's apparatus gave 14-5 tons per square inch. Until a 

 standard method for determining this point is agreed upon, it will 

 always be difficult to compare the results obtained by experimenters 

 using different extensometers. 



Table I. 



Determination of the elastic limit and coefficient of elasticity in 

 tension of nickel steel " F" (mild). 



Length upon which elongations were measured = 150 mm. (6 in.) 

 Diameter = 6085" Area = 0*2908 square inches. 



Load in 

 1,000 fts. 



Readings in -g-^Q-mm. 



Mean 

 Extension- 1 



in rofe mm - 



Differences per 

 1,000 lbs. 



Top. 



Bottom. 







312 



219 



531 



1-56 



2-5 



4 70 



4-50 



9-20 



1-70 



3 



5-10 



4-95 



10-05 



1-86 



4 



600 



5-91 



11-91 



1-81 



5 



6-9) 



6'82 



13-72 



1-89 



6 



7-82 



7-79 



15-61 



1-82 



7 



8-75 



8-70 



1743 



1-87 



8 



9-66 



9-64 



19-30 



1-85 



9 



10-58 



10-57 



2115 



1-87 



10 



11-51 



11-51 



23-02 



1-83 



11 



12-44 



12-41 



24-85 



1-93 



12 



13-41 



13-37 



26-78 



f Limit of 

 2-04 Elasticity 



13 



14-43 



14-39 



28-82 



2-60 



14 



15-70 



15-78 



31-42 





f Limit of Elasticity = 12,500 lbs. or n ' a = 43,000 ms. per sq. in. 



0-2908 (19 . 2tons) 



Coefficient of Elasticity = 27,7300,000 lbs. per sq. in. 

 = 12,375 tons per sq. in. 



1 Obtained by adding the figures in tbe preceding two columns. 



