Processing and Characterization of Maraging Steel Using LPBF Additive Manufacturing Technology

Abstract

: Manufacturing processes saw significant change with the advent of Additive manufacturing (AM), which enables manufacture of complex shaped components, light-weight designs with reduced manufacturing lead times. Production of components in Maraging steel using Laser Powder Bed fusion Technology (LPBF) AM technique has gained importance in recent times, especially in defence & aerospace sectors. Current work entails processing and characterization of Maraging Steel fabricated through LPBF technology. Using full factorial DoE, primary process parameters were identified as Laser Power - 200W, Scan speed - 800mm/sec, Hatch width - 80µm. A process window comprising of laser power and scan speed was identified corresponding to the region with an energy density of ~100J/mm 3 . Microstructural characterization of as-deposited (AD), solution treated (ST) and ST+Aged (STA) specimens using optical and SEM microscopy revealed presence of defects like lack-of-fusion, soot and spatter. Additionally, specimens were printed with modified process parameters with zig-zig scanning pattern, resulted in reduction of defects. Furthermore, micro-hardness and tensile properties have been evaluated in AD, ST and STA conditions. The tensile strength of AD is higher compared to wrought material, whereas, STA showed equivalent strength. Also, it was inferred that printing in horizontal orientation is preferable to attain higher tensile properties.