A Novel Approach to Pulsed Laser Beam Welding of Nodular Cast Iron

Nodular cast iron is widely used in industry for its excellent mechanical properties, but its poor weldability –mainly due to brittle martensite formation and high crack risk – poses challenges for refurbishing welding. Conventional Shielded Metal Arc Welding (SMAW) typically requires preheating and post-weld heat treatment (PWHT), making it impractical for large components. This study, conducted between August 2024 and May 2025, investigates the use of Pulsed Laser Beam Welding (PLW) as a novel repair method without preheating or post-weld heat treatment (PWHT). Nickel-based buttering layers and carbon steel filler wires were used under various welding parameters. Microstructural and hardness analyses showed that multilayer PLW significantly reduces martensite formation and promotes a pearlitic structure in Heat Affected Zone (HAZ). PLW joints exhibited more uniform and lower hardness than SMAW, reducing brittleness and crack susceptibility. These results highlight the potential of this novel multipass PLW process as an efficient, low-heat-input solution for repairing nodular cast iron while ensuring structural integrity.