Serrano Martínez, Víctor Manuel
Additive manufacturing by electric arc, or WAAM for its acronym in English, is a technique used for weldable materials that works using a welding wire that is deposited layer by layer until the structure previously designed by computer is achieved. The use of this technique saves material and money, among other things, as well as giving freedom in the size of the print to be achieved, which gives it a great advantage over traditional manufacturing methods. That is why it raises great interest in industries that require large parts such as aeronautics and maritime.
Currently, much focus is being given to the study of this technique, its manufacturing parameters and the properties of printed materials.
This thesis studies the microstructure and properties of a piece of austenitic 316 stainless steel with low carbon content (SS 316L, low carbon in English) previously manufactured by the company ESTIA (French Basque Country) using WAAM. Microstructural analyzes were carried out from optical and electronic microscopy, chemical analysis by EDX, characterization of the Vickers hardness of the pieces, as well as studies of the crystallographic phases and the modulus of elasticity of the material. In addition, a stress relaxation heat treatment was carried out at 600ºC, where it was intended to observe if there was an effect on the printed parts.
It has been found that the structure found differs from that which could be obtained by casting methods for an austenitic steel, obtaining vermicular or skeletal structures throughout the sample, with a δ-ferrite phase proportion of 6-8%. For their part, both the hardness and elastic modulus values are in the usual ranges for SS 316L material manufactured by other methods. Finally, although visually a change in the microstructure of the pieces is not observed, the heat treatment makes it possible to homogenize the piece, obtaining constant results throughout the piece.