Mechanical properties and microstructure characteristics of wire arc additively manufactured high-strength steels

Additive manufacturing is a revolutionary emerging technology in the manufacturing industry. Wire arc additive manufacturing (WAAM) is a metal additive manufacturing technology suitable for the production of medium to large steel elements of structure. The aim of this study is to investigate the microstructural and mechanical behavior of high-strength steels produced by WAAM through experimental program. The test specimens were additively manufactured from three types of feedstock wires (ER100S-G, ER110S-G, ER120S-G). The micro-structure characteristics of WAAM high-strength steels were identified. The tensile coupon specimens were extracted from flat regions of the WAAM runway-shaped steel tubes at five orientations theta = 0, ' 30', 45,' 60,' 90'with respect to the print direction to investigate the anisotropy of mechanical properties. Both the milled and as-built specimens were included to study the impact of geometric irregularity. The dimensions of the as-built specimens were measured using 3D laser scanning and the geometric characteristics were discussed. A total of 60 tensile tests were conducted with the assistance of digital image correlation (DIC) system in order to investigate the stress-strain responses of WAAM high-strength steels. Details of test program, including the specimen design, test setup and key test results, are presented. The anisotropy of WAAM high-strength steel specimens in terms of both the geometries and mechanical properties are discussed.