EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

With the development of additive manufacturing, new possibilities for the repair of damaged metal components are developing. Powder Laser Metal Deposition is one of these processes. In order to master and qualify this repair process, it must be characterized, controlled and optimized. This includes first of all the preparation of the part to be repaired by carrying out a pre-machining process which allows on the one hand to give access to the spray nozzle and on the other hand to remove the damaged material (for example following a corrosion phenomenon). The second step is the deposition and melting of the powder by laser in the area to be repaired. Finally, the last step consists of a finish machining. In this study, we are interested in the repair of stainless steel 316L parts with SS316L powder. Firstly, the repair process is optimized to obtain a dense, defect-free repair (e.g. porosities) and a good metallurgical bonding between the substrate and the deposit. Then, the influence of the geometry of the pre-machined groove is studied in relation to its opening angle and further optimizations of the deposition process. First results show that the groove with an opening angle of 120° is the most suitable for the repair process. Indeed, compared to the other opening angles of 135° and 105°, the spray nozzle has a better access to the bottom of the defect, the quality of the deposit is very satisfactory and the quantity of powder used is also optimized. After repair, the microstructure of the samples is observed by optical microscopy and EBSD mappings are performed to observe the transition zone between the substrate and the repair deposit. Microhardness mapping, tensile tests and Charpy impact tests are also performed. The results of these different tests are presented and discussed.