Inconel 718 structure in EBM 3D printing: the influence of process parameters on contour characteristics
(HY-industry technical centre)
Shanghai HY Industry Co., Ltd recently demonstrated with the Polymer Laboratory of East China University of Science and Technology “the effect of process parameters on the profile characteristics of Inconel 718 structure by electron beam melting”, further expanding the scope of metal additive manufacturing.
Extensive classification of additive manufacturing processes in metals
Nickel alloy Inconel 718 was used to create samples for analysis because the researchers examined the effect of process parameters on the profile characteristics of the Inconel 718 (IN718) structure manufactured by EBM. Compared with other Ni-based alloys, Inconel 718 has higher Fe, Mo, and Nb contents, while Ti and Al have lower weight percentages, resulting in better strength, corrosion resistance, good weldability and crack resistance.
Parts of EBM machine
Picture of Dr. Li Bo, East China Institute of Technology
The EBM process contains various construction parameters, which can be optimized for the following functions:
Changes can better control parameters such as molten pool size, molten powder depth, etc.
The effect of low focus (left) and high focus (right) on the molten pool
Starting from the following characteristics, powder is critical to the quality of the parts:
The researchers say: “These characteristics lead to a combination of theoretical and empirical methods.” It is important that the powder has good flowability because it directly affects the density of the part. A larger powder size density (PSD) will result in poorer fluidity, while a smaller PSD density will result in a poorer bulk density. “
Arcam A2X EBM machine internal view (left) external view (right)
Image source Shanghai HY Industry Co., Ltd
The research samples were 3D printed at University West on the Arcam A2X EBM machine. Three construction parameters were changed during the project, including voltage, focus offset, and print speed.
Inconel 718 Element W nominal composition (Persent by weight)
A total of 34 samples were created. Two samples were made with standard parameters and 5mm thickness. Others use 16 different construction parameters for 3D printing, ranging in thickness from 3mm to 5mm. Cut the sample in the build direction and cut at an offset of 1-2 mm at the middle width of the stretch rod.
The researchers explained: “A moderate cutting rate is used, and sufficient cooling fluid is provided to ensure that the sample does not overheat and maintain a straight cut.”
Hardness test according to ISO 6507 test standard
After hot mounting and grinding any sharp edges, the samples are polished, then hardness tested, and then microstructured.