Targeted Optimization of Mechanical Properties in Pearlitic Steel via Tailored Heat Treatment: The Role of Austenitization and Isothermal Quenching Parameters

To address the limitations of conventional single heat treatment parameter optimization in regulating the mechanical properties of pearlitic steels, this study aims to establish a tailored heat treatment framework by coupling austenitization control with precise isothermal quenching and to unravel the synergistic mechanisms governing multiscale microstructure evolution and resultant mechanical performance. The results show that decreasing the isothermal quenching temperature and shortening the austenitization time effectively refine pearlite nodules and colonies. The reduction of isothermal temperature plays a dominant role in refining pearlite interlamellar spacing. Among all heat treatment processes, the 900 °C‐60 min/550 °C‐10 min regime produces the most significant multi‐scale microstructure refinement. This process yields the optimal comprehensive mechanical properties, with the highest tensile and yield strength as well as good ductility (elongation ≈ 14.18%). Quantitative analysis confirms that interfacial strengthening ( σ i ) is the dominant strengthening mechanism, demonstrating that multi‐scale microstructure refinement is critical for improving strength.