Control of heating and cooling for direct laser deposition repair of cast iron components

Grey cast iron is widely used because of its combination of excellent castability and machinability. Repair and refurbishment of cast iron components can maximize their lifetime and profitability. Laser deposition is uniquely transformative in its ability to repair or modify existing components. However, laser deposition on cast iron is very difficult because of the high level of crack occurrence due to its brittle nature. This study attempted to reduce cracking through using spiraling laser passes to preheat the substrate and control the cooling rate of the material post-deposition. Stainless steel 316L was used as the deposited repair material. It will be shown that crack-free laser deposition on cast iron components can be accomplished without the addition of auxiliary equipment. The repair of a diesel engine component will be used as a vehicle to demonstrate the feasibility of the proposed methods.