中文摘要：

针对30Cr2Ni4MoV加热过程中的晶粒长大，在900℃～1250℃温度范围内实测了不同保温时间下的奥氏体晶粒尺寸。观察实验结果发现，该材料的晶粒长大在950℃～1100℃范围内存在两个温度拐点，即随着温度升高，奥氏体晶粒先是正常长大，然后在950℃以上温度时缓慢生长，二次相“钉扎”作用明显。当温度高于1050℃时，“钉扎”作用减弱，晶粒尺寸随温度升高显著增大。据此，在3个阶段内分别建立了奥氏体晶粒尺寸与温度及保温时间的关系模型。以此为依据，讨论了加热制度对30Cr2Ni4MoV大型钢锭晶粒长大及其均匀度的影响，并提出了一种新的加热制度。

英文摘要：

In order to investigate the austenite grain growth for 30Cr2Ni4MoV rotor steel during heating process, specimens were heated in a vacuum electric furnace at different holding temperatures （from 900℃ to 1250℃） for different holding time （from 20mn to 300min） and their austenite grain size were observed. It is found that there exist two turning points of temperature for grain growth in the range of 950℃ to 1100℃. As the temperature increasing, the grain grows normally at first, while when the temperature is beyond 95℃, the grain growth turns to be slowly due to the strong piweffects of the second phase. When the temperature is above 1050℃, the pin-effects become weak and grains grow evidently with the increasing of temperature. Based on the experimental results, mathematical models were established for different heating periods. According to these models, the effects of heating schedule to the grain growth and distribution is also discussed.