The
intermediate transformation microstructure of low-carbon bainite steel was analyzed, which had
been deformed in
the non-recrystallization temperature range, relaxed for a period of time and cooled by various
cooling rates. The influence of relaxation process and cooling rate on the
intermediate transformation structure type
and
microstructure refinement was revealed. The results show that in a slowly cooled sample after relaxation the
transformation structure is mainly granular bainite and the effect of relaxation refinement is not marked. But while
the cooling rate is fast enough (>10℃/s), the main microstructure is lath-like bainite, and relaxation effect can be
seen clearly After relaxation, the lath of bainitic ferrite is more fine and sharp, the morphology of M/A constituent
is film-like. Comparing with the non-relaxed sample, it is clearly seen that the relaxation of deformed austenite ben-
efits to obtain ultra-fine lath-like bainite structure. At the same cooling rate, the amount of M/A constituent decrea-
ses in the relaxed sample.