The 41xx series is a low alloy steel with a small amount of chromium and molybdenum added for increased depth of strength/hardness. The last two numbers (15) represent nominal carbon content of 0.15%. Strength/hardness and ductility, as well as most other mechanical properties will vary with thermomechanical history (heat treatment, hot/cold working). Take a look at ASTM A500, the strength of this alloy will be similar to a 1015 carbon steel only greater thickness capability.
