Averylargenumberoffine Fe2Nb particles are present in the
grains during normalizing, which shows that the tensile strengths of
the normalized specimens in the three steels increase to different
degrees, mainly owing to the precipitation hardening effect offine
Fe2Nb particles. Meanwhile, the elongation of the steel 1 after normalizing is remarkably improved probably due to the discontinuous
formation of Fe2Nb at grain boundaries, which minimizes the negative effect of reticular precipitates. The morphology of TiN clusters
almost showed no change after normalizing at 850°Cfor2h,which
is still the major factor for the slight increase in the elongation of
steels 2 and 3. Hence, it is inferred that the mechanical properties of
thespecimensarestronglyinfluenced by the size, morphology and
distribution of the precipitates in the steels.