An attempt has been made to establish a relationship between hardness and t
ensile properties for various single structured steels: ferrite, pearlite,
bainite, and martensite. It is found that the proportionality constant Ay O
f hardness to yield strength changes from 5.79 to 3.17 and is highest for t
he ferrite steel and lowest for the tempered martensitic steels. A less pro
nounced change was found in the proportionality constant AT Of hardness to
tensile strength (from 3.97 to 2.72), A dependence on microstructure of the
proportionality constant at 8% strain A(0.08) was found as well. This diff
erence in A was found to be attributable mostly to the effect of different
work hardening behaviours owing to different microstructures, Regression an
alysis shows that hardness can be expressed as a function of accessible mat
erial parameters such as composition, grain size, and transformation temper
atures for various single structured steels within a certain degree of accu
racy. (C) 2001 IoM Communications Ltd.