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为实现制造业在线控制,钢中扩散型动力学曲线的数字化已提到日程。虽然近年来采用高精度热膨胀仪进行测量,不同作者得到的动力学方程参数差别仍然较大。究其原因,实际上是试验数据拟合方法有待改进。为此,从动力学曲线提取20个试验数据,一方面改用极大似然法MLE拟合Avrami方程形状参数,另一方面,进一步调整孕育期和名义相变结束时间使试验数据内禀斜度/峭度和Avrami方程的斜度/峭度期望值相一致。根据贝茵体等温转变和恒速加温奥氏体转变的试验数据进行计算,发现这两组动力学曲线都可用威布尔/Avrami唯象表述。
To achieve online control of the manufacturing industry, the digitization of diffusion kinetic curves in steels has been mentioned on the calendar. Although high-precision thermal dilatometer has been used for measurement in recent years, the difference of dynamic equation parameters obtained by different authors is still large. The reason, in fact, the experimental data fitting method needs improvement. For this reason, 20 experimental data were extracted from the kinetic curve. On the one hand, the maximum likelihood method was used to fit the Avrami equation shape parameters. On the other hand, further adjustment of the incubation period and the nominal phase transition end time made the experimental data The degree / kurtosis is consistent with the expected slope / kurtosis of the Avrami equation. Calculated on the basis of the experimental data of the bainitic transformation and the constant-temperature-heated austenite transformation, it is found that both kinetic curves can be expressed by the Weibull / Avrami phenomenology.