Statistical Modeling of Wire and Arc Additive Manufactured Stainless Steel 304: Microstructure and Fatigue

Abstract

Single-bead walls were fabricated using stainless steel (SS) 304 wire and arc additive manufacturing (WAAM). The primary objective is to statistically characterize critical material properties of the build to make comparisons with wrought material. The quality of the build is demonstrated by the size distribution and spatial location of porosity in the build. Deviations in the thermal history as a function of the location in the build, especially as the vertical height of the build increases, cause differences in material properties which are statistically investigated. The material behavior and statistical variances along the horizontal direction of the build compared to perpendicular differences in location is significant. Optical microscopy and electron back-scatter diffraction are used to estimate statistically key geometric properties of grains. A preliminary investigation for fatigue using the strain life approach has been conducted to evaluate the effect of the build process and the location dependence on life. A generalized Weibull distribution is proposed to model the statistical variability of fatigue life data.