Metal AMS
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48 - Additive manufacturing of austenitic stainless steel non-planar and small thickness product by WAAM process


Naval Group invests in the WAAM technology development since 2015 and started to produce several case studies in 2019. One of the main emblematic applications highlighted by several media, is the manufacturing of a 3D-printed propeller mounted on a French navy ship. Moreover, Naval Group investigates the field of non-planar and small thickness products as well. This category of products is mainly manufactured by conventional processes such as casting and forging that often lead to large amounts of compacity defects. These non-qualities affect cost and time delivery of the products. Hence, the WAAM process aims to guarantee better quality level and, as a result, to reduce cost and time overruns. The WAAM process can also achieve notable savings on raw material, thanks to the buy-to-float ratio that can be less than 1.5 for this kind of pieces. These cumulated reasons have led Naval Group to give some interests to the 3D-printing process of thin and complex products. One specific product that has been identified is a volute of a hydraulic system that has a particularly complex design. A 1:1 scale demonstrator of this product has been printed with the WAAM process on the Naval Group’s R&D equipment. Many challenges have been taken up to achieve the manufacturing of the product, such as the management of the welding robot trajectories or the choose of the sequence of deposition. As the demonstrator of volute is made from austenitic stainless steel 316L, a specific attention has been paid to thermal conditions during the fabrication in order to master the final metallurgy inside the part. As a result of these developments, the demonstrator was successfully achieved. However, several issues occurred during the deposition such as excessive distortion of the surfaces of the volute. In order to avoid the occurrence of similar issues on further fabrications, Naval Group is aiming to increase the readiness level of some technological bricks such as new NDT processes or thermomechanical simulation. Another challenge for this category of part is the possibility of reaching smooth surface conditions, especially on difficult to access areas. For this purpose, sequence of deposition as well as surface finishing processes are both highly important.


Naval Group, Indret, France

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48 - Additive manufacturing of austenitic stainless steel non-planar and small thickness product by WAAM process



4:25 pm -4:45 pm


Room 6