TESTING OF ADDITIVELY MANUFACTURED STAINLESS STEEL MATERIAL AND CROSS-SECTIONS

Powder bed fusion (PBF) additive manufacturing has the potential for significant impact on the construction industry due to its ability to produce complex and free-form components with high-precision. However, the size of components is limited by the build envelope of PBF machines. Laser welding offers a means of joining small individual PBF parts together to create larger-scale parts. This paper investigates the microstructure and material properties of stainless steel coupons with and without laser-welded joints, in conjunction with the structural performance of stainless steel circular hollow sections (CHS) at the cross-sectional level, with all specimens printed by PBF. The PBF base material exhibited a typical cellular microstructure, while the weld material consisted of equiaxed, columnar and cellular dendrite microstructures. The proof strengths of the weld were lower than those of the base metal, and the strengths of the PBF base metal were dependent on the build direction – the vertically built coupons showed lower proof strengths than the horizontal coupons. The axial resistances of the PBF CHS are safely predicted by the EN 1993-1-4 design provisions and the deformation-based continuous strength method (CSM).