Microstructure and mechanical properties of AF1410 ultra-high strength steel using laser additive manufacture technique

AF1410 ultra-high strength steel plate sample is fabricated using the laser additive manufacturing (LAM) technique and homogenization treatment combined with the traditional heat treatment of AF1410 is conducted as the heat treatment. Microstructures, hardness and tensile properties of the steel are investigated. Results show that the microstructures of as-deposited AF1410 exhibit some characteristics of directional solidification with a hardness of about 360 HV. After the heat treatment, the directional solidification microstructure disappears while a refined microstructure and tempered martensite are obtained with hardness of about 510 HV. Meanwhile, yield strength and tensile strength at room temperature of the heat treated steel reach to 1490 MPa and 1610 MPa, respectively, with the elongation of 12.8% and the reduction of area of 70%.