STRENGTH OF STEEL. 



363 



soft state, and about 45 tons per square inch when it has 

 been hardened in oil. This hardening is effected by 

 immersing the steel at a temperature of 1,450 Fah. in a 

 bath of cool oil. Col. Maitland further states that the 

 chemical composition is about 0'25 to 0'50 per cent, of 

 carbon and 0'80 to 0'05 per cent, of manganese. The 

 following figures comprise the chief test results quoted by 

 Col. Maitland : 



TENSILE STRENGTH OF GUN STEEL. 



The above figures are not average results, but are 

 selected from a large number of those quoted. 



