for concentrations of up to 1.2 percent. If 1 percent Mn is used, the hardenability factor
is 4.46. Similarly, a 2 percent concentration of chromium is only a little more
effective, giving a factor of 5.36. Table 3.1 is not complete (a notable omission being
vanadium), and alloying elements may also have significant secondary influences.
Nevertheless, the equations of Table 3.1 provide a useful guide to the selection of the
most economical means for obtaining a required level of hardenability.
Most alloy steels can be classed as either “through-hardening” or “carburizing,”
the latter being used where a tough core and relatively shallow, hard surface layer
are desired. Nitriding and other surface-hardening processes are also used.