 (Note that all tank-building nations had abandoned the use of carburized hardened carbon steel in favour of the increased protection offered by rolled nickel-chromium homogeneous steel armour plate, cast nickel-chromium steel and cast ferro-nickel based armoured alloys by the mid-1920s onwards).By comparison the German 37 mm PaK 35/36 could penetrate up to 44 mm of perpendicular rolled homogenous armour plate at 100 metres with PzGr.18.APHE, up to 64 mm of perpendicular hardened carbon steel at 100 metres with PzGr.18.