Method for preparing high-strength low-density steel through laser powder bed melting

The invention provides a method for preparing high-strength low-density steel through laser powder bed melting. The method comprises the following steps: proportioning according to customized low-density steel components, and preparing low-density steel powder with a required particle size suitable for 3D printing; after laser powder bed melting process parameters are optimized, 3D printing is conducted through laser powder bed melting forming equipment, and a high-density sedimentary-state low-density steel part is obtained; wherein the technological parameters for melting by adopting the laser powder bed are as follows: the laser power is 110-160W; the scanning speed is 780 to 1420 mm/s; the scanning interval is 60 to 110 microns; the powder spreading thickness is 30-70 microns; the low-density steel comprises the following components in percentage by mass: 10-20 wt% of Mn; 4 to 6 wt% of Al; 5 to 7 wt% of Ni; 0.4 to 0.6 wt% of C; and the balance of Fe. According to the method, the sedimentary-state low-dens