| Title |
A Study on Microstructure and Mechanical Properties in the Down-skin area of 17-4PH Stainless Steel using Laser Powder Bed Fusion Addictive Manufacturing |
| Authors |
김영경(Yeong-gyeong Kim) ; 어두림(Du-Rim Eo) ; 이승호(Seung-ho Lee) ; 최균석(Kyun-suk Choi) |
| DOI |
https://doi.org/10.5370/KIEE.2024.73.2.427 |
| Keywords |
Laser-Powder Bed Fusion; 17-4 Precipitation Hardening Stainless Steel; Down-skin; Martensite |
| Abstract |
17-4 Precipitation Hardening Stainless Steel(17-4PH SS) is a material with excellent corrosion resistance and high strength and has recently been widely used to make parts of complex shapes through the Laser Powder Bed Fusion(L-PBF) process. The high strength is expressed by fine and uniform precipitation of Cu deposits in the martensite matrix tissue. However, in the L-PBF process, laser is selectively irradiated on metal powder to melt and solidify the local area repeatedly, and even if 17-4 PH SS powder of the same composition is used and the process conditions are kept uniform, the cooling rate and thermal history of each area are different depending on the shape of the sculpture. As a result, it appears a different microstructure(martensite fraction, etc.) depending on the area of the final stack, resulting in uneven mechanical properties. In particular, in the case of L-PBF products with complex geometries, heat dissipation is not smooth in the Down-skin area, so stacking failures frequently occur , or even if they are successful, unexpected problems with weak mechanical property occur frequently. These results could be suggested for observing microstructure and mechanical properties on the Down-skin area of 17-4PH Stainless Steel processed by Laser-Powder Bed Fusion. |