Porosity reduction in metal with hybrid wire and arc additive manufacturing technology (WAAM)

Among different additive manufacturing (AM) methods, wire and arc additive manufacturing (WAAM) is the most suitable for manufacture of large-size metal components due to high deposition rates, which are rather higher than that for a powder laser and electron beam technology. AM processes are connected with high residual stresses and deformations due to excessive heat supply and high deposition rate. Influence of the process conditions, such as supplied energy, wire feed rate, welding speed, features and sequence of deposition etc., on thermal prehistory and resulting residual stresses in machine components (which were processed via additive-modular treatment), requires additional understanding. Additionally, low accuracy and surface cleanness during the process restricts use of AM technology with wire addition. This paper describes a hybrid (additive + subtractive) manufacturing approach for a steel component based on wire and arc additive manufacturing. The hybrid wire and arc additive manufacturing (WAAM) is used to describe a sequence of manufacturing steps. The main idea of the suggested approach is minimization of porosity in WAAM production process of machine components; as a result, quality of deposed metal layer improves. A steel wall was produced by hybrid (additive + subtractive) manufacturing. The non-destructive testing methods (penetrant inspection, ultrasound inspection, and X-ray inspection) were used to confirm high quality of metals.