· The effect of heat treatment
on the properties (hardness)
of various iron-carbon
alloys is illustrated. · The alloys are first quenched to give
martensite,
then heated above the T-T-T "nose" and isothermally
transformed to get
pearlite, and then heated to 600 - 700 C to obtain spheroidite. · In all cases, increased carbon
content
increases the materials hardness. Ductility
is increased by the sequence of treatments
shown.
From:
Guy & Hren, "Elements of Physical Metallurgy," Addison Wesley
(1974)