THE EFFECT OF AUSTENITE VOLUME FRACTION ON THE DEFORMATION RESISTANCE OF 409 STAINLESS STEELS DURING HOT-STRIP ROLLING

Abstract

The mill log data obtained from the hot-strip rolling of 409 stainless steels were analyzed in order to investigate
the effect of the chemical composition on the deformation resistance. The results showed that the deformation
resistance depended sensitively on the austenite stabilizing capability of the material chemistry, suggesting
the austenite volume fraction as a dominant factor in controlling the deformation resistance. Deformation
resistance ratio (DRR) was defined as a ratio of the deformation resistance of a two-phase (ferritic+austenitic)
microstructure to that of a fully ferritic microstructure. The dependence of DRR on the austenite volume
fraction appeared to be linear, which was also observed by the plane strain compression tests performed on the
laboratory specimens with various austenite volume fractions. The implication of this result is that during the
hot-strip rolling of 409 stainless steels with a two-phase microstructure, these steels are likely to deform in an
equal-strain manner.