A Novel Approach to Pulsed Laser Welding of Nodular Cast Iron Without Preheating and Post-Weld Heat Treatment

Nodular cast iron is widely used in industry for its excellent mechanical properties, but its poor weldability mainly due to brittle martensite formation. Conventional Shielded Metal Arc Welding (SMAW) typically requires preheating and post-weld heat treatment (PWHT). This study, conducted between August 2024 and May 2025, investigates the use of Pulsed Laser Welding (PLW) as a novel repair method without preheating or post-weld heat treatment (PWHT). Microstructural and hardness analyses showed that multi-layer 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