Microstructure and mechanical behavior of laser additive manufactured AISI 316 stainless steel stringers

• We produce large aspect ratio stainless steel structures with very good tensile properties.
• The flexural tests proved that the cladded layers had very good formability.
• The appearance of delta ferrite, which is deleterious to the corrosion properties, was avoided.

Laser additive manufacturing of stainless steels is a promising process for near net shape fabrication of parts requiring good mechanical and corrosion properties with a minimal waste generation. This work focuses on high aspect ratio AISI 316 steel structures made by superposition of sequential layers. A special nozzle for precise powder delivery together with a monomode fiber laser allowed producing high quality steel stringers on AISI 316 steel substrates. Although the stringers average compositions were inside the austenite plus ferrite range, only austenite phase was verified. The cladded structure presented some internal pores and cracks, responsible by the low Young’s moduli. However, the tensile properties were similar to the base material and other literature results. The three-point flexural tests also produced good results in terms of formability. The fabricated structures proved to be useful for use in mechanical construction.