Comprehensive Analysis of Residuel stress and Multiscale Compression Properties in Laser Powder Bed Fusion additive manufactured H13 Steel
In this study, using laser powder bed fusion (LPBF) H13 steel with a "cellular structure" as the basic unit, we explored the origins of multiscale mechanical heterogeneity by altering the preheating temperature. Comprehensive microstructural characterization, in-situ residual stress analysis, and multiscale compression tests were employed. The results indicate that the "cellular units" of LPBF H13 steel are larger when preheated at 500°C compared to 200°C (1.13 ± 0.22 μm vs. 0.88 ± 0.22 μm), although they remain consistent throughout the entire build height of 78 mm. In contrast, residual stress analysis revealed that preheating at 200°C resulted in a residual stress (RS) distribution that decreased from 527 ± 10 MPa at the top to 165 ± 12 MPa at the bottom, while preheating at 500°C significantly mitigated the formation of residual stress, with an average RS value of only 32 ± 29 MPa. The compression test show that the 200°C preheated samples showed greater variation and higher compression strength at the top superior 2900 MPa, whereas the 500°C preheated samples exhibited more uniform compression properties with compression strength about of 3100 MPa.
Keywords:
Additive manufacturing; Residual stress; H13 steel; Microstructure and compressive properties.