Material characterization of WAAM stainless steel

With the aim of assessing the mechanical properties of WAAM stainless steel, extensive experimental investigations have been carried out on different types of specimens: (i) plates printed with layer-by-layer continuous strategy and (ii) bars printed with dot-by-dot strategy. 

Regarding WAAM plates, the experimental characterization has been carried out on two types of specimens: (i) machined specimens, from which information on the material properties is analyzed, and (ii) as-built specimens, from which information related to the geometrical irregularities and their influence on the mechanical behavior is studied. From the tests on the machined specimens, first a microstructural analysis has been carried out with the colleagues from the Metallurgic Department of University of Bologna. Then, the key material properties have been estimated from tensile tests on machined specimens to assess the anisotropic nature of WAAM stainless steel. From the tests on the as-built specimens, additional geometrical characterization has been carried out. The mechanical behavior of as-built specimens was studied through tensile tests to evaluate the influence of geometrical irregularities on the mechanical response of WAAM elements.

Regarding WAAM bars, the experimental characterization has been carried out on bars printed at different build angles to estimate the effect on the key mechanical properties. Additionally, three-point bending tests and compression tests were carried out to estimate the flexural and buckling behavior of the printed bars.

References

Laghi, V., Palermo, M., Gasparini, G., Girelli, V. A., & Trombetti, T. (2020). Experimental results for structural design of Wire-and-Arc Additive Manufactured stainless steel members. Journal of Constructional Steel Research, 167, 105858.

Laghi, V., Palermo, M., Tonelli, L., Gasparini, G., Ceschini, L., & Trombetti, T. (2020). Tensile properties and microstructural features of 304L austenitic stainless steel produced by wire-and-arc additive manufacturing. The International Journal of Advanced Manufacturing Technology, 106(9), 3693-3705.

Tonelli, L., Sola, R., Laghi, V., Palermo, M., Trombetti, T., & Ceschini, L. (2021). Influence of Interlayer Forced Air Cooling on Microstructure and Mechanical Properties of Wire Arc Additively Manufactured 304L Austenitic Stainless Steel. steel research international, 92(11), 2100175.

Laghi, V., Palermo, M., Gasparini, G., Girelli, V. A., & Trombetti, T. (2021). On the influence of the geometrical irregularities in the mechanical response of Wire-and-Arc Additively Manufactured planar elements. Journal of Constructional Steel Research, 178, 106490.

Laghi, V., Palermo, M., Tonelli, L., Gasparini, G., Girelli, V. A., Ceschini, L., & Trombetti, T. (2022). Mechanical response of dot-by-dot wire-and-arc additively manufactured 304L stainless steel bars under tensile loading. Construction and Building Materials, 318, 125925.