How convection on the substrate affects the thermal history of the build in direct laser deposition—finite element analysis

• Published in: International journal of advanced manufacturing technology 2018-06, Vol.96 (9-12), p.3471-3480
• Main Authors: Hochmann, E. A., Salehinia, I.
• Format: Article
• Language: English
• Subjects: Basins; CAE) and Design; Coefficients; Computer-Aided Engineering (CAD; Construction; Convection; Engineering; Finite element method; Geological time; Heat transfer; Industrial and Production Engineering; Laser deposition; Mechanical Engineering; Media Management; Melting; Multilayers; Original Article; Substrates; Temperature; Temperature gradients; Thermal analysis; Thermal cycling; Three dimensional analysis
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-018-1696-4

A transient three-dimensional thermal analysis using finite element method was conducted to determine the effect of varied convection applied on the substrate on the thermal history of a multi-layer/multi-pass (per layer) build in direct laser deposition (DLD) of SS316 steel. The effect of the coefficient of heat convection was studied on thermal cycling, thermal gradient, and the output net heat during the deposition process. The results showed that the convection coefficient on the bottom surface of the substrate has negligible effects on the thermal history of the build, thus proving that this parameter may not be used to control the thermal history, and consequently, the microstructure of the build. The results also showed 12% increase in the dissipated heat from the build to the substrate when the coefficient of heat convection changed from 0 to 10,000 W/m 2  K. In comparison to the current knowledge, modeling a multi-layer/multi-pass (per layer) geometry provided a better understanding of the thermal history of the build during the DLD process.