|
A
short, intensive but very precise in line cooling of the
rolled bar is imparted
in process through a proprietary system. This treatment
results in a cooled hardened periphery. On further cooling
of the bar in atmosphere, a thermel exchange (
) occurs between the resultant bar structure is a distinct
tempered martensite at periphery and a fine grained ferrite-pearlite
structure in the central zone.
The
bar produced by the above quenching and self tempering process
(QST) has unique qualities of desired high strength and
toughness combined with excellent ductility with bars having
elongation (A5) values of 18 to 25% |