Microstructure and mechanical properties of 316L stainless steel of selected laser sintering

Abstract

In recent years, additive manufacturing (AM) has received global attention, because the AM can manufacture irregular and complex-shaped parts and reduce material waste. In this paper, the 316L stainless steel powder was made into a structure conforming to the size of ASTM E8 by the selected laser sintering (SLS). The AM parameters were set as fixed laser power (220 W) and layer thickness of 0.03 mm, as well as scanning speed (900 mm/s and 800 mm/s), different annealing temperatures (750°C, 850°C and 950°C), and time (3 minutes, 6 minutes and 9 minutes). The results show that the optimal tensile strength was 639 MPa when the scanning speed was 800 mm/s, and the annealing temperature and time were 750°C and 3 minutes, respectively. In addition, the maximum elongation was 43% when the annealing temperature and time were 850°C for 6 minutes and 9 minutes, and 950°C for 9 minutes. The as-SLS of fast and slow scanning speeds were compared, the maximum tensile strength increased from 575 MPa to 639 MPa (increased by 11.1%), and the elongation increased from 21% to 32% (increased by 13.1%). The significant records of the 316L mechanical properties are extremely important for the fundamental understanding of SLS.