Papers by Akash Rajendra Sali
International Journal of Engineering Materials and Manufacture, 2021
This study explores the application of Electron-Beam Welding (EBW) for joining Laser Powder-Bed-F... more This study explores the application of Electron-Beam Welding (EBW) for joining Laser Powder-Bed-Fused Inconel 718 (L-PBF IN718) superalloy. Three different levels of electron beam speed and beam current were explored to give nine different electron beam heat inputs for experimentation. To define the weld characteristics microhardness, tensile, and fractography analysis using scanning electron microscopy, optical microscopy, and energy dispersive spectroscopy were conducted. Typical nail-shaped weld geometry was observed with penetration depth proportional to heat input. Most welded samples exceeded the yield strength (600MPa) and tensile strength (920MPa) requirements from the ASTM F3055 specifications for additively manufactured IN718, however, the specimens did not meet the ductility requirements (27%). Brittleness of the weld was attributed to the presence of brittle secondary phases in the weld matrix, and unfused metal powder of adjacent L-PBF layers. Post-processing heat treat...
Procedia Manufacturing, 2020
This paper presents a study of Electron Beam Welding (EBW) of rolled Inconel 718 (IN718) plates. ... more This paper presents a study of Electron Beam Welding (EBW) of rolled Inconel 718 (IN718) plates. The experiment utilized nine different heat inputs at three different levels of welding speed and beam current. The weld quality was characterized and ranked based on weld geometry, microhardness and mechanical properties. Fusion area and weld penetration depth were found to be proportional to the heat input. Microhardness measurement showed a wider and softer weld zone at the beam entrance. Voids, found at weld bottoms when welding at the highest beam power of 3250 watt and scanning speed exceeding 0.78 m/min, can be removed by a suitable machining process. All samples but one had tensile strength exceeding the specification for rolled IN718 (837 MPa); ductility of welded specimens also met the specification (57%) when welding with heat input less than 225 J/mm. At low heat inputs, the welded samples fractured outside of the weld zone and indicated their exceptional weld strength. The samples welded at higher heat inputs cracked and fractured at the weld. These results provide a benchmark for comparison with future study on EBW of selective laser melted IN718.
International Journal of Engineering Research and, 2016
This paper gives a complete insight on the systematic procedure required to be followed for desig... more This paper gives a complete insight on the systematic procedure required to be followed for design of a three axis robotic system and its implementation as a 3D printer. The mechanical structure of the system is designed based on dimensional and load carrying requirements. The system is equipped with a suitable material extrusion system along with a control system that allows its use as a 3D printer based on the principle of fused deposition modelling.
This paper explores the feasibility of welding Inconel 718 (IN718) and compares the quality of el... more This paper explores the feasibility of welding Inconel 718 (IN718) and compares the quality of electron beam welded samples produced by rolling and laser-based powder bed fused (L-PBF). Electron beam heat input, varying in the range 175-300 J/mm, was the main parameter in welding. Microhardness, tensile properties, and fractography study using both optical and scanning electron microscopy were employed to analyze and compare the quality of the welded samples. Energy dispersive x-ray analysis was used to identify chemical compositions of different phases on the fractured surfaces. Large voids were observed at high heat inputs (≥ 213 J/mm). Excellent weld penetration was obtained and was proportional to the beam heat input. Both yield and tensile strength of the welded L-PBF’ed materials exceeded those of rolled materials and met the minimum requirement from ASTM specification; however, the ductility of welded L-PBF’ed material did not. The brittleness of these L-PBF’ed materials came...
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Papers by Akash Rajendra Sali