通过单道次压缩及冷却试验,研究了低温区变形温度对具有超细原始奥氏体晶粒的含Nb钢组织的影响。结果表明,在给定的试验条件下,试验钢的真应力-真应变曲线出现峰值,且峰值应力随温度的增加先增大再减小;随着变形温度的降低,组织中铁素体晶粒得到细化;在低于Ar3温度下变形时,铁素体晶粒尺寸差异增大,铁素体硬度值分布较分散。
Effect of deformation temperature on austenite transformation of Nb microalloyed steel with ultrafine initial austenite grain was studied by single hit compression and cooling tests. The results showed that the stress-strain curve present peaks, with the increasing of the deformation temperature, the peak stress increases first and then decreases; With the decreasing of the deformation temperature, the ferrite grain was refined; When the deformation temperature decreases to 750℃and 720℃ respectively, below Ar3, the difference of ferrite grain size was magnification, and the degree of the ferrite grain hardness dispersed distribute.