Залежність кількості аустеніту від температури при нагріванні загартованої штампової сталі 4Х3Н5М3Ф

• Дата: 2025
• Автори: Radchenko, O. K., Sydorchuk, O. M., Fedoran, Yu. O., Askerov, M. G., Gogaev, K. O.
• Формат: Стаття
• Мова: Ukrainian
• Опубліковано: Physico- Technological Institute of Metals and Alloys of the NAS of Ukraine 2025
• Теми: штампова сталь; аустеніт; нагрівання; рівняння Арреніуса; ефективна енергія активації
• Онлайн доступ: https://momjournal.org.ua/index.php/mom/article/view/2025-1-3
• Назва журналу: Metal Science and Treatment of Metals

The study utilizes the results of a previously conducted high-temperature X-ray phase analysis of quenched die steel 4Kh3N5М3F obtained by electroslag chill casting. An exponential model-free dependence of the amount of austenite on temperature was constructed. The obtained dependence, calculated using the Origin software with a high determination coefficient (0.99397), describes the increase in the amount of austenite as the steel heating temperature rises throughout the investigated temperature range (from 20 to 800 °C). Unfortunately, the coefficients in this dependence lack a clear physical meaning, which led to an attempt to describe the change in austenite content using the Arrhenius equation. Using the linear regression method and Excel software, the material constants of the Arrhenius law were calculated only for the three highest temperature points. It was found that the dependence of the amount of austenite (in mass %) is well described by the Arrhenius law (R² = 0.98397) in the temperature range from 450 to 800 °C, while the residual austenite content at room temperature does not conform to this dependence. A comparison of the calculated effective activation energy of austenite formation with existing literature data (1500-450 kJ/mol for tool steels and 40 kJ/mol for hypereutectoid boron steel (22MnB5)) showed that the obtained value is relatively low. In our view, the low calculated effective activation energy is associated with three factors reducing its magnitude: the presence of retained austenite in the steel structure after quenching, a fine-dispersed nonequilibrium martensitic structure, and the low heating rate of the samples during the study. The established patterns of phase composition changes concerning the amount of austenite in quenched 4Kh3N5М3F steel during heating within the studied temperature range allow determining its efficiency for hot stamping tools at different operating temperatures.