Investigation on microstructure and wear properties of 9Cr5Mo roll steel modified by warm shot peening

Rolls are prone to surface wear, cracks, fractures, and other defects during operation. To enhance the wear resistance and fatigue life of 9Cr5Mo roll steel, its surface was reinforced using the warm shot peening (WSP) process with varying parameters. The wear performance of the roll steel, both before and after WSP, was evaluated by investigating surface integrity, microstructural evolution, and the underlying wear mechanisms. As the temperature of the shot peening increased, the hardness initially decreased, then increased, and finally decreased again. Similarly, the compressive residual stress exhibited an initial increase followed by a decline. The optimal combined effect of warm shot peening, yielding the greatest wear resistance, was achieved under a shot peening intensity of 0.28 mmA, a shot peening time of 30 s, and a shot peening temperature of 400°C. Furthermore, the morphology of the worn surfaces revealed that the primary wear mechanisms in the original specimens were adhesive and abrasive wear, with abrasive wear being the dominant mechanism in the WSPed specimens. [Display omitted]