27 research outputs found
INFLUENCE OF ABNORMAL AUSTENITE GRAIN GRAIN GROWTH IN QUENCHED ABNT 5135 STEEL
Grain size in the steels is a relevant aspect in quenching and tempering heat treatments. It is known that high
austenitizing temperature and long time provide an increase in austenitic grain sizes. Likewise, after hardening of low
alloy steel, the microstructure consists of martensite and a volume fraction of retained austenite. This paper evaluates
the influence of austenite grain size on the volume fraction of retained austenite measured by metallographic analyses and
X-ray diffraction. The Mi
and Mf
temperatures were calculated using an empirical equation and experimentally determined
by differential thermal analysis. The mechanical behavior of the steel was evaluated by Vickers microhardness testing.
Differently from other results published in the literature that steel hardenability increases with the austenite grain size,
it was observed that the increase in austenite grain promotes greater volume fraction of retained austenite after water
quenching