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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。
The hot compressive deformation of 30Cr2Ni4Mo V steel for large-scale low-pressured rotors was carried out on a Gleeble-1500D thermal simulator at a temperature of 900-1250 ℃, a strain rate of 0.01-1s-1, and a maximum strain of 0.69. The critical conditions for dynamic recrystallization and microstructural changes during this process are presented. At the same time, the thermal activation energy, the thermal deformation equation and the dynamic recrystallization grain size model of 30Cr2Ni4Mo V steel were obtained by fitting the experimental data, and the Zener-Hollomon parameters were calculated, and then the statistical analysis of the mixed crystallinity . The results show that when the deformation temperature is higher and the deformation rate is smaller, the dynamic recrystallization is more likely to occur. Meanwhile, under the condition of dynamic recrystallization, the greater the deformation, the more dynamic recrystallization occurs. When the dynamic recrystallization to about 10%, the maximum degree of mixed crystal, and then began to drop to 43% to a minimum, followed by little change with the recrystallization.