An increase in technical requirements related to the prediction of mechanical properties of steel engineering components requires a deep understanding of relations which exist between microstructure, chemical composition and mechanical properties. This paper is dedicated to the research of the relation between steel hardness with the microstructure, chemical composition and temperature of isothermal decomposition of austenite. When setting the equations for predicting the hardness of microstructure constituents, it was assumed that: (1) The pearlite hardness depends on the carbon content in a steel and on the undercooling below the critical temperature, (2) the martensite hardness depends primarily on its carbon content, (3) the hardness of bainite can be between that of untempered martensite and pearlite in the same steel. The equations for estimation of microstructure constituents’ hardness after the isothermal decomposition of austenite have been proposed. By the comparison of predicted hardness using a mathematical model with experimental results, it can be concluded that hardness of considered low-alloy steels could be successfully predicted by the proposed model.

中文翻译：

---

奥氏体等温分解后显微组织成分的硬度预测

与预测钢工程部件的机械性能有关的技术要求的提高，需要对微观结构，化学成分和机械性能之间存在的关系有深入的了解。本文致力于研究钢的硬度与奥氏体的等温分解组织，化学成分和温度之间的关系。在设定用于预测显微组织成分硬度的方程式时，假定：（1）珠光体硬度取决于钢中的碳含量和低于临界温度的过冷度；（2）马氏体硬度主要取决于其硬度（3）贝氏体的硬度可以介于同一钢中的未回火马氏体和珠光体之间。提出了等温分解奥氏体后组织硬度的估算方程。通过将数学模型的预测硬度与实验结果进行比较，可以得出结论：所提出的模型可以成功地预测所考虑的低合金钢的硬度。