ST-41 steel has relatively low surface hardness and fatigue resistance, requiring surface treatment to improve its mechanical properties. This study analyzed the effects of temperature variation and catalyst type in the pack carburizing process on the hardness, fatigue resistance, and microstructure of ST-41 steel. The results showed that the highest hardness of 275 HV was obtained at 950°C using the eggshell catalyst, while the highest fatigue life reached 912,966 cycles at 950°C. ANOVA confirmed that temperature, catalyst type, and their interaction significantly affected the hardness and fatigue resistance (p < 0.05). SEM-EDS analysis also revealed the formation of a more homogeneous martensitic layer after pack carburizing.

Keywords: ST-41 steel, pack carburizing, hardness, fatigue resistance, microstructure (ANOVA).