Session: 03-01 Metals: Post Processing Topics

Paper Number: 95101

95101 - Effects of Hot-Forging and Post-Deposition Heat Treatment on Hsla Steels Produced by Waam 

Additive manufacturing (AM) is a fabrication process based on layer-by-layer deposition that enables the creation of relatively complex three-dimensional structures. The Wire and Arc Additive Manufacturing (WAAM) variant makes use of an electric arc as an energy source for metal deposition from a welding wire. This technique is well-known for its high deposition rate and ability to produce large parts when compared to other technologies. However, great challenges entail the non-homogeneous microstructure formation, affected by the intense and cyclic heat input, which leads to anisotropic and weak mechanical properties. Since then, this work presents a sensitive optimization of parameters (in terms of Wire Feed Speed, Travel Speed, and Voltage) of a WAAM variant, known as HF-WAAM (Hot-forging WAAM), that aims to mitigate pores and produce equiaxial grains in HSLA steels. Also, previous results confirm the microstructure grain refinement, and the formation of the α-Fe phase was observed by a Synchrotron X-ray Diffraction (SXRD) analysis. A minor secondary phase, possibly retained austenite, had its intensity reduced while stress-relief heat treatment (HT) occurred with two different temperature patamars. Likewise, the specimens presented a reduction of more than 35 % in hardness for the most intense HT. Thereby, the effects of hot forging during deposition followed by heat treatment showed to be promising for the enhancement of the material characteristics, and further mechanical tests are expected to corroborate this trend. Besides, other techniques can be explored to promote grain refinement, like the addition of inoculants particles into the deposited bead.

Presenting Author: Igor Oliveira Felice FCT/UNL

Presenting Author Biography: Ph.D. student of the Department of Mechanical and Industrial Engineering at FCT/NOVA University. Gratuated in mechanical and aeronautical engineering by UNA and UFU universities, respectively. M.Sc. in Materials and Fabrication Processes by UFU with research in wire and arc additive manufacturing (WAAM).

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