Research of anisotropy of low-cycle fatigue characteristics of 316LSi stainless steel produced by wire-arc additive manufacturing

When manufacturing parts of complex geometry using additive technologies, anisotropy of mechanical properties occurs in materials. The assessment of the anisotropy of static and cyclic properties is carried out, among other things, using experimental studies on samples cut in different directions from the deposited billet. The purpose of the work is to study the anisotropy of mechanical characteristics under cyclic and static loads of 316LSi stainless steel obtained by wire-arc welding. The tests were carried out on samples cut in three different directions from the deposited billet under static tension. It has been established that the elastic properties of steel are primarily influenced by the direction of sample cutting. The effect of sample orientation on the mechanical behavior of steel under low-cycle fatigue with controlled axial deformation parameters is analyzed. It is shown that the samples cut in the vertical and diagonal directions with respect to the plane of the deposited layers have the highest and lowest cyclic durability with equal values of the amplitude of deformation. The results of comparing experimental low-cycle fatigue curves with curves whose parameters were calculated based on the Basquin – Manson – Coffin equation and data from static tensile tests are presented. The possibility of predicting the characteristics of low-cycle fatigue for different directions of sample cutting is shown. The results obtained can be used to modify the technological parameters of wire-arc surfacing to reduce the effect of anisotropy of the mechanical properties of additive materials.