CFD Simulation and Surface Modification of SG Cast Iron for Hot Rolling Applications

Abstract

The wear resistance and heat dissipation of hot rolling mill rollers are critical factors affecting their durability and operational efficiency, particularly under extreme thermal and mechanical conditions. This study investigates the surface modification of SG iron rollers through tungsten laser cladding, aiming to improve these properties. A comprehensive approach, combining Computational Fluid Dynamics (CFD) simulations and experimental trials, was employed to evaluate the performance of tungsten-cladded rollers relative to untreated ones. The results revealed a 10-18% improvement in heat dissipation for tungsten-cladded rollers, attributed to enhanced heat transfer rates and better cooling efficiency. The analysis of fluid flow patterns, water volume fraction, and cooling angles demonstrated that tungsten cladding allowed for more effective heat management and uniform cooling across the roller surface. In the experimental trials, the mechanical properties of SG iron showed significant enhancement after laser cladding. The microhardness of the cladded surface increased by 59%, from 220 HV to 350 HV, offering improved resistance to surface deformation and wear. Furthermore, the wear resistance improved by 35% reduction in wear loss, as the tungsten and MoS₂/WC composite coatings provided a strong protective barrier against abrasion. Additionally, the Coefficient of Friction (COF) was reduced by 43%, from 0.7 to 0.4, due to the lubricating properties of MoS₂, minimizing frictional heat and energy loss during operation. These findings reveal the effectiveness of tungsten laser cladding as a surface modification technique for SG iron rollers, with practical implications for improving the durability and operational efficiency of hot rolling mill rollers.