Heat Transfer Analysis and Thermal Effect Prediction of Seamless Flatness Roll Laser Cladding

The seamless flatness roll enables precise, non-destructive flatness measurement of cold-rolled strips, ensuring consistent high-quality production. Prolonged use in production makes the roll surface prone to scratches and wear, and repeated offline grinding may eventually erode the entire hardened layer. Although the roll core remains structurally intact, the roll is often prematurely retired due to surface degradation. This study investigates the feasibility of applying laser cladding-based additive remanufacturing technology to restore the flatness roll. A key challenge in this process is that embedded sensors within the roll cannot be temporarily removed. Consequently, the high temperature generated during laser cladding may be applied to these components, potentially exceeding their thermal tolerance. To address this issue, this study conducts an in-depth analysis of the heat transfer behaviour during the laser cladding process of the flatness roll. A planar Gaussian heat source model, incorporating a normal-direction attenuation function and spiral feed control, was developed. Additionally, a comprehensive finite element model of the entire roll, the birth–death element technique, was constructed. A detailed thermal conduction path from the laser spot to the installation hole and subsequently to the internal component was established. Finally, experimental validation was performed using an industrial cladding platform with a wireless temperature acquisition system. The simulation results demonstrated good agreement with the experimental data. Under the current process settings, the predicted temperature of the internal component exceeds its allowable thermal limit when the roll length surpasses 820 mm, highlighting the need for further optimisation of the cladding process.