Hadftcld.— 9. 



^ 



Analysis: C. .42, Mn. .74%. 



Treaiment: As Forg-ed. 



The Structure shows grains of Ferrite on a ground mass 

 of Pearlite. 



Magnification 100. 



Etched with 5% Solution Meta-Nitro-Benzol-Sulphonic 

 Acid. 



Figure it. 



Photomicrog-raphs showing- that the Structure of a Gun Tube Steel is 

 independent of the etching reagent 



