OBRABOTKAMETALLOV technology Vol. 27 No. 1 2025 Introduction Modern development of science and technology stimulates active implementation of innovative technologies in various fields, including the production of metal parts. Additive technologies, despite their considerable potential, still face the problems of low productivity and high cost. The desire to optimize these processes has led to the development of additive manufacturing methods based on metal wire deposition [1–3]. This approach, compared to the use of powder materials, significantly reduces the fabrication time and lowers the cost of blanks due to the lower price of wire. However, the wire deposition method often results in insufficient surface quality, requiring additional machining. In addition, specific cooling conditions during the wire deposition process result in a microstructure with increased hardness compared to conventional manufacturing methods such as forging or casting. This is especially true when heat-resistant materials are used [4, 5]. To demonstrate the advantages and disadvantages of the cladding method, let us consider a highstrength, heat-resistant alloy — Inconel 625. Its high cost and specific properties allow us to demonstrate the advantages and disadvantages of this method. The high hardness achieved when depositiong Inconel 625 wire necessitates specialized machining methods aimed at optimizing processes and minimizing costs [6-8]. In the layer-by-layer wire deposition process, each new layer is deposited on the previous layer, which in turn undergoes repeated heating and rapid cooling [9]. This heating and cooling cycle has a significant effect on the formation of the microstructure. In the case of martensitic steels, a relatively low critical cooling rate favors the formation of a martensitic structure with high hardness, as confirmed by studies [10, 11]. However, when selective laser melting (SLM) or wire arc additive manufacturing (WAAM) is used with Inconel, the situation becomes more complicated. Due to high melting temperatures and complex phase transformations, there is anisotropy of mechanical properties in the finished part. Grain size, porosity, and consequently, strength properties depend on the direction of measurement, as shown in the works [12, 13]. This is attributed to the non-uniform thermal cycle during the layer-by-layer build process. Work [14] demonstrates the anisotropy of the mechanical properties in parts fabricated by additive methods, and work [15] indicates the possibility of partial compensation for this effect through heat treatment, which, however, increases production costs. Furthermore, rapid cooling during SLM or WAAM can lead to the formation of a hardened surface layer with extremely high hardness on the surface of workpieces made from heat-resistant alloys, which significantly complicates subsequent machining. For Inconel, this effect can be even more pronounced due to its unique properties and higher melting temperature. The parameters of the wire arc additive manufacturing (WAAM) process, such as substrate temperature, torch speed, and trajectory [16–17], significantly affect the microstructure formation and, consequently, the mechanical properties of the resulting workpiece. Even when these parameters are optimized, structural defects such as local surface hardening, inhomogeneity of phase distribution, and micropores inevitably occur, which reduces the predictability of mechanical properties. WAAM, as one of the additivemanufacturing methods, is characterized by the formation of an anisotropic microstructure with non-uniform distribution of stresses and properties over the part volume [18-20]. This is due to the layer-by-layer nature of the wire depositing, non-uniform heating and cooling, and internal stresses arising during melt crystallization. In addition to the inhomogeneity of the structure, WAAM technology often leads to the formation of workpieces with poor surface quality, requiring mandatory subsequent machining [21–23]. Grain size, porosity, and consequently, strength properties depend on the direction of measurement, as shown in [12, 13]. This is due to the inhomogeneity of the thermal cycle during the layer-by-layer build-up process. The work of [14] demonstrates the anisotropy of the mechanical properties of products fabricated by additive methods, while the work of [15] indicates that it is possible to partially compensate for this effect by heat treatment, which, however, increases the manufacturing costs. The complex thermal cycles inherent in WAAM technology result in the formation of an inhomogeneous microstructure in the obtained billets, which significantly complicates subsequent machining. This heterogeneity is manifested in significant variations in hardness, strength, and other mechanical properties
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