Cost-effective laser metal deposition of 304L stainless steel for repairing and enhancing 316L and mild steel engineering components

This study presents a cost-effective additive manufacturing (AM) approach using Laser Metal Deposition (LMD) to enhance the durability and repair of 316L stainless steel and mild steel engineering components. By depositing a protective 304L stainless steel layer, this method extends the components' life cycle in harsh environments while offering significant cost savings, as 304L powder is less expensive than 316L. The research optimized the LMD process by exploring high scan speeds (up to 8000 mm/min) and powder feed rates (up to 50 g/min) to enhance productivity and ensure an economically viable repair solution. Defect-free layers with strong metallurgical bonding were successfully deposited on both substrates using an optimal energy density of 100-200 J/mm[Formula: see text], an interaction time of 0.5-1.6 seconds, and a powder feed rate of 10-30 g/min. The resulting 304L layers demonstrated enhanced microhardness (around 200 HV) compared to both the 316L and mild steel substrates and corrosion resistance comparable to 316L (and superior to mild steel), with a low corrosion rate of 0.002 mpy in a 3.5% NaCl solution. These results confirm that LMD is a viable and economical solution for repairing and protecting engineering components in various industries such as automotive, pharmaceutical, and marine. The study also highlights the necessary precautions for high-power LMD processes.