﻿Stresses on the Elastic Properties of Iron and Steel. 421 



torsion-tension tests in fig. 5. This compression line, how- 

 ever, only holds, so far as known, for low carbon- steel. 



The variation of the unit elongation at the elastic limit for 

 different torsional stresses is shown graphically in fig. C (2). 

 It is seen that, with the exception of the cases A and B 

 (i. e. steel tubing 0*85 and 0'90 inch inside diameter), the 

 torsional stress lowers the unit elongation at the elastic limit. 

 Fig. 6 (1) also shows the change in the modulus of elasticity 

 in tension caused by the different torsional loads. There 

 seems to be no regularity in this case, although in most cases 

 the modulus of elasticity was lowered slightly by the torsioual 

 stress. 



The results of the tests, as shown by the curves, might be 

 summed up in the statement, that the presence of a torsional 

 stress lowers the unit stress and unit strain at the elastic limit 

 in tension and also lowers the modulus of elasticity, somewhat. 

 These same facts are also shown by Table I. 



Table I. 



Stress Applied. 



Inside 



Diameter 



in 



Elastic 

 Limit in 

 pounds per 



Modulus of™ Um l 



Elasticity in E1 f °5g at J? n 



I t J at Elastic 



pounds per T ,_. f .„ 





inches. 



sq. inch. 



I sq. inch. 



inches. 



Steel Tubing. 











Simple Tension 



0-85 



17,000 



27,400,000 



•00062 



l/3Tors.-El. Ten.... 



0-85 



16,000 



26.600,000 



•00060 



2/3 Tors.-El. Ten.... 



0-85 



12,090 



27,200,000 



•00044 



3/3 Tors.-El. Ten.... 



085 



9,000 



17,000,000 



•00053 



Simple Tension 



090 



28,000 



29,700.000 



•00094 



1/3 Tors.-El. Ten.... 



0-90 



24.000 



27,800.000 



•00086 



2/3 Tors.-El. Ten.... 



0-90 



17,000 



25.000,000 



•00068 



3/3 Tors.-El. Ten.... 



0-90 



14,000 



16,200,000 



•00086 



Simple Tension 



0-50 



20,000 



33,300,000 



•00080 



1/6 Tors.-El. Ten. .. 



0-50 



18,000 



27,200,000 



•00066 



2/6 Tors.-El. Ten.... 



0-50 



16,000 



29,600,000 



•00054 



3/6 Tors.-El. Ten.... 



0-50 



14,000 



28,000,000 



•00050 



4/6 Tors.-El. Ten.... 



0-50 



12,000 



26,000,000 



•00046 



5/6 Tors.-El. Ten.... 



0-50 



10,000 



30,300,000 



•00033 



6/6 Tors.-El. Ten.... 



050 



8,000 



26,600,000 



•00030 



nickel- Steel Solid Eou 



ids. 









Sim pie Tension 





56,000 



35,000,000 



•0016 



1/3 Tors.-El. Ten.... 





52,000 



29,800,000 



•00174 



2/3 Tors.-El. Ten.... 





44,000 



28,800,000 



•00152 



3/3 Tors.-El. Ten.... 





20,000 



28,800,000 



•0067 



Low Carbon-Steel Solid 



Bounds. 









Simple Tension 





34,000 1 



30,800,000 



•0011 



1/3 Tors.-El. Ten.... 





32,000 



30,500,000 



•00105 



2/3 Tors.-El. Ten.... 







24,000 



25.800,000 



•00083 



3/3 Tors.-El. Ten.... 





16,000 



25,200,000 



•00063 



