Study on monotonic and cyclic properties of WAAM low-carbon steel thick plate

Wire Arc Additive Manufacturing (WAAM) holds significant potential for application in building structures due to its high deposition efficiency. While numerous studies have focused on the mechanical properties of thinwalled WAAM low-carbon steel, primarily under monotonic loading, there is a limited exploration of WAAM low-carbon steel thick plates (thickness higher than 10 mm) subjected to cyclic loading, which is critical for key structural components in seismic conditions. In this study, thick plates with the thickness of 16 mm and 24 mm were fabricated. Coupons were extracted from three different angles. Subsequent monotonic tensile tests and metallographic analysis revealed that, prior to heat treatment, the thick plate displayed minimal anisotropy, with approximately 8 % lower yield strength and 3 % lower elongation in the built direction. Heat treatment can improve the elongation and reduce data dispersion. Following this, cyclic tests under various load protocols within the range of 0.5% to 2.0% were conducted. Results demonstrated that the hysteresis curves are full, with minimal variation in hysteresis performance among different sampling angles. The evolutions of peak stress, backstress, and yield surface radius with equivalent plastic strain are determined and analyzed. Finally, parameters in the modified isotropic/kinematic hardening model were calibrated, and the average mechanical properties in three sampling angles were employed to characterize the behavior of WAAM low-carbon steel under cyclic loading. The research outcomes laid a foundation for further finite element analysis of WAAM low-carbon steel structures in seismic conditions.