中文摘要：

在实际生产中大锻件不同部位因变形不均匀而导致晶粒尺寸不一。为了探究这一现象,利用Gleeble-1500D热模拟试验机在1000℃、应变速率0.1 s-1、变形量5%-55%时模拟了大型低压转子用30Cr2Ni4Mo V钢的变形过程,研究了其在随后正火过程中晶粒大小随保温时间的变化规律。结果表明,与未变形试样相比,经过相同正火的变形试样的晶粒得到明显细化。在900℃正火的初期,变形量小于35%时,晶粒尺寸随变形量的增加而减小;当变形超过35%后,变形量对晶粒尺寸影响不大,且随保温时间的延长,不同变形量变形后试样的晶粒均会持续长大,正火5 h可以消除变形量对试样晶粒度的影响。

英文摘要：

in the actual production, the grain size of different parts in the large forgings is different due to the uneven deformation. In order to explore this phenomenon, the deformation process of 30Cr2Ni4MoV steel for large low pressure rotor was simulated at 1000℃ ,the stain rate of 0.1 s-1 and the deformation 5%-55% by using the Gleeble-1500D thermal simulation testing machine. The relation between the grain size and the holding time in normalizing process of the steel was studied. The results show that compared with the non-deformed specimen, the grain of the deformed specimen after the same normalizing is significantly refined. At the beginning of the normalizing at 900℃, when the deformation is less than 35%, the grain size decreases with the increase of the deformation. When the deformation rate is higher than 35%, the deformation has little effect on the grain size. And with the extension of holding time, the grain size of the samples after different deformation will continue to grow. Normalizing for 5 h can eliminate the influence of deformation on grain size of the sample.