Description / Abstract:
This SAE Standard prescribes the procedure for making
hardenability tests and recording results on shallow and medium
hardening steels, but not deep hardening steels that will normally
air harden.
Included are procedures using the 25 mm (1 in) standard
hardenability end-quench specimen for both medium and shallow
hardening steels and subsize method for bars less than 32 mm (1-1/4
in) in diameter. Methods for determining case hardenability of
carburized steels are given in SAE J1975.
Any hardenability test made under other conditions than those
given in this document will not be deemed standard and will be
subject to agreement between supplier and user. Whenever check
tests are made, all laboratories concerned must arrange to use the
same alternate procedure with reference to test specimen and method
of grinding for hardness testing.
For routine testing of the hardenability of successive heats of
steel required to have hardenability within certain limits, it is
sufficient to designate hardenability simply in terms of distance
from the quenched end to the point at which a certain hardness is
obtained. This designation may also be adequate for comparing
steels of different compositions to see whether they have similar
hardenability.
Hardenability limits for specifying steel in this manner are
obtained by measuring the hardenability of a steel which has proved
satisfactory for the use intended. The hardenability test may be
used in this way as an empirical test.
For new components where manufacturing experience is lacking,
hardenability data may be effectively used to estimate the hardness
profile provided by any given steel. Attendantly, the ability to
predict hardenability from chemical composition has become
increasingly important when comparing various steel grades or
developing new steels for specific applications. One such procedure
is described in Appendix A. Other hardenability prediction methods
are available from the selected references in Section 2. However,
it should be emphasized that the use of any hardenability
prediction procedure does not preclude the importance of conducting
Jominy end-quench tests to determine the actual hardenability of
any specific grade of steel.
Hardenability data may be used to estimate hardnesses obtainable
with any steel in new machine parts not yet in production and not
similar to any parts on which production experience is available.
Various hardenability application methods are described in the
selected references, Section 2.1, 23 to 25. It appears none of
these methods are precise, but these are often useful for
estimation purposes. Final correlation on actual parts is
necessary.