As a critical load-bearing component of the transmission system in cement rotary kilns, the thrust roller device imposes high-quality requirements on cast steel materials. However, casting defects such as cracks,porosity, and sand inclusions still will occur during manufacturing. By analyzing the chemical composition and mechanical properties of the cast steel grade ZG42Cr1Mo used for thrust rollers, the J507 low-hydrogen electrode was selected. Corresponding repair processes, including drilling stop holes, machining excavation, and grinding removal, were developed to address linear and nonlinear defects in the thrust rollers. During the repair process, critical parameters such as preheating temperature, electrode drying, and interpass temperature were strictly controlled. Multi-layer and multi-pass welding techniques were employed to ensure welding quality. Post-weld insulation and slow cooling treatments were implemented to prevent crack formation, followed by magnetic particle inspection and hardness testing. This repair solution effectively resolved quality instability issues in thrust rollers, enhanced product competitiveness, achieved significant economic benefits, and holds high promotional value.