Fatigue and fracture characteristic of hypoeutectoid pearlitic R7T steel used in railway applications

This study comprehensively investigates the mechanical properties, fatigue behavior, and fracture toughness of hypoeutectoid pearlitic R7T steel employed in railway wheel manufacturing. Utilizing a combination of rotating bending fatigue tests and compact tension (CT) specimens, the fatigue life, crack growth rate, and fracture toughness of the material were systematically evaluated. Experiments were conducted under cyclic loading conditions in both radial and tangential orientations to simulate in-service conditions. Microstructural examination using scanning electron microscopy (SEM) revealed the role of inclusions, dimpled rupture, and cleavage features in failure mechanisms. Hardness measurements across different wheel rim regions indicated minimal anisotropy. The findings provide critical insights into the structural performance and failure resistance of R7T steel under cyclic loading conditions, offering valuable implications for the design and maintenance of wheel steel.