This work focused on laser powder bed fusion (LPBF) of H13 tool steel to examine microstructure and melt pool morphology. Experiments were conducted with varying laser power (P) in the range of 90-180 W and scan speed (v) in the range of 500-1000 mm/s. layer thickness (l) and hatch spacing (h) were kept constant. Volumetric energy density (γ) was calculated using the above process parameters. In order to find a relation between the recorded density and top surface roughness with changing process parameters, set of equations were derived using the non-dimensional analysis. For any chosen values of laser power, scan speed, hatch spacing and layer thickness, these equations help to predict top surface roughness and density of LPBF processed H13 tool steel. To confirm the universal relation for these equations, data of In718 and SS316L processed in LPBF was input which gave a R-square of >94% for top surface roughness and >99% for density. A closed box approach, response surface model, was also used to predict the density and surface roughness which allows only in the parametric range. Material microstructures were examined to identify the melting modes such as keyhole, transition and conduction modes. X-ray diffraction data revealed that there was a presence of retained austinite in all the H13 printed samples. Elongated and equiaxed cellular structure were observed in higher magnifications due to solidification rate and thermal gradient.
| Identifer | oai:union.ndltd.org:unt.edu/info:ark/67531/metadc2137613 |
| Date | 05 1900 |
| Creators | Channa Reddy, Sumanth Kumar Reddy |
| Contributors | Dahotre, Narendra B., Joshi, Sameehan, Sharma, Shahsank |
| Publisher | University of North Texas |
| Source Sets | University of North Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Format | Text |
| Rights | Public, Channa Reddy, Sumanth Kumar Reddy, Copyright, Copyright is held by the author, unless otherwise noted. All rights Reserved. |
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