中文摘要：

利用Gleeble-1500D热模拟试验机在温度为900~1250℃、应变速率为0.01~1 s-1、最大应变量为0.69的实验条件下对大型低压转子用钢30Cr2Ni4Mo V进行热压缩变形实验,研究了发生动态再结晶的临界条件和在此过程中的显微组织变化。同时,通过对实验数据进行拟合,得到30Cr2Ni4Mo V钢的热激活能、热变形方程以及动态再晶晶粒尺寸模型,并计算出Zener-Hollomon参数,然后对试样的混晶度进行统计分析。结果表明,当变形温度越高、变形速率越小时,越易发生动态再结晶,同时在能够发生动态再结晶的条件下,变形量越大,动态再结晶发生越充分。当动态再结晶进行到10%左右时,混晶程度达到最大,随后开始下降到43%时达到最小,之后随着再结晶的进行变化不大。

英文摘要：

The hot compression deformation test for low pressure rotor made of steel 30Cr2Ni4 Mo V was carried out by Gleeble- 1500 D thermal simulation testing machine under conditions of 900- 1250 ℃,stain rate 0. 01- 1 s- 1and maximum strain 0. 69,the critical condition of dynamic recrystallization and microstructure evolution process were investigated. At the same time,the activation energy,the thermal deformation equation and dynamic recrystallization grain size model of steel 30Cr2Ni4 Mo V were obtained by fitting analysis of experimental data,and the Zener- Hollomon parameter was calculated,then the mischcrystal fineness of steel 30Cr2Ni4 Mo V was analyzed statistically. The results show that higher deformation temperature and lower strain rate are advantageous to dynamic recrystallization.When the dynamic recrystallization occurs,the dynamic recrystallization fraction increases with the increase of strain. When the rate of the dynamic recrystallization is about 10%,the mischcrystal fineness is up to the maximum level,then it begins to fall until the minimum43%. Furthermore,the fraction of recrystallization has little change.