New continuous cooling transformation (CCT) equations have been optimized to calculate the start temperatures and critical cooling rates of phase formations during austenite decomposition in low-alloyed steels. Experimental CCT data from the literature were used for applying the recently developed method of calculating the grain boundary soluble compositions of the steels for optimization. These compositions, which are influenced by solute microsegregation and precipitation depending on the heating/cooling/holding process, are expected to control the start of the austenite decomposition, if initiated at the grain boundaries. The current optimization was carried out rigorously for an extended set of steels than used previously, besides including three new solute elements, Al, Cu and B, in the CCT-equations. The validity of the equations was, therefore, boosted not only due to the inclusion of new elements, but also due to the addition of more low-alloyed steels in the optimization. The final optimization was made with a mini-tab tool, which discarded statistically insignificant parameters from the equations and made them prudently safer to use. Using a thermodynamic-kinetic software, IDS, the new equations were further validated using new experimental CCT data measured in this study. The agreement is good both for the phase transformation start temperatures as well as the final phase fractions. In addition, IDS simulations were carried out to construct the CCT diagrams and the final phase fraction diagrams for 17 steels and two cast irons, in order to outline the influence of solute elements on the calculations and their relationship with literature recommendations.

对新的连续冷却转变（CCT）方程进行了优化，以计算低合金钢在奥氏体分解过程中相形成的起始温度和临界冷却速率。来自文献的实验性CCT数据用于应用最近开发的计算钢的晶界可溶成分以进行优化的方法。这些成分受加热/冷却/保持过程的影响，受溶质微偏析和析出的影响，如果在晶界处引发，则有望控制奥氏体分解的开始。除了在CCT方程中包括三个新的溶质元素Al，Cu和B之外，当前的优化是针对一组较以前严格使用的钢进行的。方程的有效性是 因此，不仅由于加入了新元素，而且由于在优化过程中添加了更多的低合金钢，因此提振了产量。最终优化是使用小型标签工具进行的，该工具从等式中丢弃了统计上无关紧要的参数，并使其谨慎使用更为安全。使用热力学动力学软件IDS，使用本研究中测得的新实验CCT数据进一步验证了新方程式。对于相变起始温度以及最终相分数，该协议都是好的。此外，进行了IDS模拟，以构建17种钢和两种铸铁的CCT图和最终相分数图，以概述溶质元素对计算的影响及其与文献建议的关系。不仅由于加入了新元素，而且在优化过程中添加了更多的低合金钢，也因此得到了提高。最终优化是使用小型标签工具进行的，该工具从等式中丢弃了统计上无关紧要的参数，并使其谨慎使用更为安全。使用热力学动力学软件IDS，使用本研究中测得的新实验CCT数据进一步验证了新方程式。对于相变起始温度以及最终相分数，该协议都是好的。此外，进行了IDS模拟，以构建17种钢和两种铸铁的CCT图和最终相分数图，以概述溶质元素对计算的影响及其与文献建议的关系。不仅由于加入了新元素，而且在优化过程中添加了更多的低合金钢，也因此得到了提高。最终优化是使用小型标签工具进行的，该工具从等式中丢弃了统计上无关紧要的参数，并使其谨慎使用更为安全。使用热力学动力学软件IDS，使用本研究中测得的新实验CCT数据进一步验证了新方程式。对于相变起始温度以及最终相分数，该协议都是好的。此外，进行了IDS模拟，以构建17种钢和两种铸铁的CCT图和最终相分数图，以概述溶质元素对计算的影响及其与文献建议的关系。