84 



TABLE III. 



Showing Variability of P- Limit. 



Bar No. 1. 

 Carbon 



0.27 



f 

 Manganese 0.58 % 



Silicon 0.214% 



Analysis { Ph 0.024% 



Sulph 0.036% 



Copper 0.028% 



Nickel 4.552% 



De.?cription of Test. 



— o =• ,^-, 



Note Effect of Test. 



:cc 



Original 



45 hours after . . . 

 10 minutes after 



118 hours after and in 450' 

 r.bath 



22 hours after 



After in bathat21S- F. 



500 hours after . . 

 10 minutes after 



29.3 

 •26.4 



24.8 



29.0 

 28.2 

 29.2 



28.0 

 26.0 



=■96.0 Overstrain. 

 98.0 P-lirait destroyed. 

 •lOO.O P-limit destroyed. 



116.0 P-limit restored by annealing. 



■117.0 Overstrain. 



114.0 Overstrain restored by anneal- 

 ing. 



116.0 Overstrain restored by rest. 



116.0 Test to destruction 15% elonga- 

 tion, 42% contraction in 8". 



Bar No. 2. 



1 Original 



2 I 15 hours after... 



3 2 weeks after ... 



4 ' 10 minutes after 



5 I After in bath at 190'- F 25.3 



Overstrain. 

 Overstrain. 

 P-limit destroyed. 

 P-liniit destroyed. 

 P-limit not restored. 



"•'■■Indicates that the test overstrained the metal. 

 E. taken between limits of stress of 25,000 to 85,000. 



