STKKNGTH OF WROUGHT IRON. 



The above values are for tension and compression. 

 It will be observed that the failing stress in compression, 

 which is really the elastic limit, is not very different from 

 the elastic limit stress in tension. The strength of ship 

 and boiler plates is less when tested across the fibre than 

 with the fibre, the difference amounting to from 1 to 1'75 

 tons per square inch. 



The two bars tested by Mr. Bennett were cut 

 from the same bar, the first turned for a length of lOin., 

 and the second simply nicked down to the same 

 diameter. The results obtained in this case are similar to 

 those already given. 



Typical load-strain diagrams for wrought iron in 

 tension and compression are given on Fis. 169 and 

 170. 



1 80. Mr. Stromeyer's Tests. In the following table 

 are given the results obtained by Mr. Stromeyer in 

 tension tests of wrought iron which had been treated in 

 different ways : 



LOWMOOR IRON. 



Unprepared 12-5 22-1 6-67 



Quenched red-hot in cold water ... 24-5 7'02 



Annealed blue-hot two nights... 13-4 21-7 18-71 



four ... 14-1 22-1 14-16 

 Bent cold to a radius of 15in. 



and flattened 14-1 23-2 18-78 



Bent hot (blue to straw) and 



flattened ... ' 12-5 23-6 7-06 



Twisted cold (90 in 12in. and 



back) 15-2 2:V2 8-46 



Twisted hot (blue to dark straw 



and back) ... 16-3 24-6 16-33 



