EFFECT OF THE STABILITY OF RETAINED AUSTE NITE ON ELONGATION IN HOT-ROLLED HIGH-STRENGTH STEELS

The effect of plastic stability of retained austenite on elongation wa s investigated using Fe-0.17%C-1.99%Si-1.77%Mn hot-rolled high strengt h steel sheets produced in the mill-scale test. The results obtained a re as follows; (1) Total elongation, uniform elongation and local elon gation have a tendency to be improved with the increase of the plastic stability of retained austenite when volume fraction of retained aust enite is nearly equal. (2) The plastic stability of retained austenite has a tendency to be improved with the increase of carbon contents in retained austenite. (3) The volume fraction of retained austenite at 15% tensile strain, kp and n-value over very small strain interval hav e strong relation to elongation. They are considered to be indexes for the effect of the plastic stability of retained austenite on elongati on.