Application of the magnetic method to control the deformed state of ER308LSI steel samples obtained by additive growing

Additive technologies (AT) used for the manufacture of materials and products are being introduced precipitately in modern industry. The technology of electric arc cultivation (Wire Arc Additive Manufacturing (WAAM)) is of considerable interest due to a relatively low cost of the equipment and surfaced materials, as well as due to an essential level of understanding welding processes. The cultivation of metal layers and the manufacture of volumetric parts of various geometric shapes in this case is carried out by welding wire. Chromium-nickel steels are widely used as surfaced materials for three-dimensional printing with metals. However, given the specifics of complex structural and formative processes in the implementation of WAAM, there is a need for additional studies of the structure and properties of the materials obtained. The goal of this study is to apply modern non-destructive methods of structural degradation control in the process of uniaxial stretching of ER308LSI steel obtained by the WAAM electric arc additive cultivation method. At the same time, metallographic and magnetic studies were carried out, along with the analysis of changes in microhardness during deformation of samples cut along and across the printed layers. The features of the stages of structure degradation upon uniaxial stretching and the behavior of magnetic parameters of the material were analyzed. It is shown that uniaxial stretching of WAAM-made samples leads to the formation of a large number of structural defects in the form of deformation bands, discontinuities and microcracks, the appearance of which is accompanied by a significant change in the yield strength, microhardness and in the values of coercive force H c . Based on the obtained Hc values, a parameter of the magnetic anisotropy ( A magn ), which reflects the nature of the change in the coercive force in samples cut both along and across the direction of surfacing was introduced. However, the character of these changes for longitudinally and transversely (relative to the deposited layers) cut samples is different. The results obtained can be used in diagnosing the deformed state of WAAM products.