Manufacturing of blanks from martensitic stainless steel by the Waam method

Introduction. The aim of the study is to identify the patterns of microstructure formation and mechanical properties of low-alloy structural steel blanks manufactured by Wire Arc Additive Manufacturing (WAAM). Additionally, the effect of process parameters and the distance from the substrate on the chemical composition, grain size distribution, microhardness, and anisotropy of mechanical properties is investigated. Materials and methods. The samples were fabricated using pulsed wire arc deposition with ER70S-6 welding wire on an E335GC steel substrate, forming vertical wall-shaped blanks. The chemical composition, microstructure, microhardness, and tensile properties of specimens cut in horizontal and vertical directions relative to the build orientation were analyzed. Optical metallography, optical emission spectroscopy, microhardness testing, and uniaxial tensile tests were used to study the structural and mechanical characteristics of the WAAM-produced blanks. Results and discussion. It was established that the WAAM-fabricated samples exhibit pronounced structural and chemical heterogeneity along the build height. The upper layers are characterized by a coarse grained dendritic structure, while the underlying regions consist of a fine-grained ferrite–pearlite microstructure formed as a result of repeated recrystallization. A distinct grain size gradient increasing with distance from the substrate was observed. Variations in chemical composition across the cross-section were revealed, associated with diffusion processes and partial evaporation of alloying elements. Mechanical testing showed that the tensile strength of the central regions is comparable to that of conventionally produced steels of similar grade, while noticeable anisotropy of strength and ductility is observed depending on the specimen orientation. Conclusion. The study demonstrates the complex influence of WAAM process parameters on microstructure evolution and mechanical behavior of low-alloy structural steel blanks. The revealed relationships between thermal conditions, microstructural gradients, and mechanical properties emphasize the need for process optimization to achieve more uniform and predictable performance of WAAM-produced components. Proposals for practical application and direction of future research. The obtained results can be applied in the development of WAAM technologies for manufacturing, strengthening, and repair of structural and machine-building components. Future research will focus on optimizing deposition parameters and studying the effect of post-deposition heat treatment on microstructural homogeneity and mechanical properties

Anisotropy · Ductility (Earth science) · Grain size · Indentation hardness · Martensite · Martensitic stainless steel · Microstructure · Ultimate tensile strength · Welding · Additive Manufacturing Materials and Processes · High Entropy Alloys Studies · Welding Techniques and Residual Stresses