含铌微合金钢低温区静态软化行为

Static Softening Behavior in Low Temperature Area of Nb Microalloyed Steel

通过两道次压缩变形实验对含Nb微合金钢静态软化行为进行了研究。结果表明:含Nb微合金钢静态再结晶临界温度随应变量增大而降低;随原始奥氏体晶粒尺寸增加而升高。温度高于静态再结晶临界温度时,含Nb微合金钢的静态再结晶激活能为常数(170.589 kJ/mol);温度低于静态再结晶临界温度时,由于Nb的碳氮化物应变诱导析出,含Nb微合金钢的静态再结晶激活能为温度的函数,静态再结晶临界温度可通过再结晶激活能与温度倒数的关系曲线来确定。

The static softening behavior was studied by double hit compression tests. The results show that the static recrystallization critical temperature of tested steels decreases with increasing the strain and increass with in- creasing the initial austenite grain size. The static recrystallization activation energy, about 170. 589 kJ/mol, was unvaried when the temperature was higher than the static recrystallization critical temperature. However, the static recrystallization activation energy became a function of temperature because the static recrystallization was inhibited by the strain induced precipitation of niobium carbonitride when the temperature was lower than the static recrys- tallization critical temperature, and the static reerystallization critical temperature could be determined by the rela- tionship between activation energy and reciprocal of the absolute temperature.