Wave deformation hardening in hybrid WAAM technology: finding optimal modes using 08G2S steel as an example

Problem. The widespread adoption of additive manufacturing technologies, particularly the WAAM method, is hindered by the insufficient level of mechanical properties of synthesized products: microstructural heterogeneity, porosity, and high residual stresses. A promising direction for solving this problem is the application of hybrid technologies combining additive manufacturing with subsequent processing. Aim. To determine the rational range of wave deformation hardening (WDH) modes when used in hybrid technology for synthesizing products by the WAAM method, ensuring an increase in the mechanical properties (hardness and impact toughness) of the synthesized product. Methods. Samples of 08G2S steel produced by the WAAM method were subjected to WDH using a specialized setup with a hydraulic pulse generator. In a three-stage experiment, the sample heating temperature (300–700 °C), the overlap coefficient of plastic imprints (0.3–0.7), and the processing frequency (every layer, every third, every fifth, and every seventh deposited layer) were varied. Vickers hardness through the depth, the degree of hardening, and KCU impact toughness were measured. Results. It was established that maximum hardening is achieved at a temperature of 500 °C, an overlap coefficient of 0.3–0.6, and processing of every third deposited layer. This made it possible not only to increase the material hardness by 8–13 % at a depth of more than 12 mm and increase impact toughness by up to 14 %, ensuring uniformity of properties throughout the product volume, but also to improve the productivity of the hybrid process. Conclusions. The developed methodology makes it possible to control effectively the mechanical properties of WAAM products by determining rational parameters of wave deformation hardening. The proposed approach can be used in the manufacture of critical components in mechanical engineering.