Integrated approach to stainless steel 316L parts repair for pitting corrosion using laser metal deposition

With the development of additive manufacturing (AM) and in particular laser metal deposition (LMD), new possibilities for the repair of damaged metal components are developing. In this context, the use of AM offers an efficient way to restore functionality to a defective part, especially for high value parts. In this study, a numerical chain is proposed to automate the repair process of stainless steel naval parts affected by pitting corrosion. An ellipsoidal repair volume is generated at each iteration by intersecting the nominal surface and the ellipsoid surface, which initial dimensions are those of the pitting corrosion defect. This optimization considers dimensional and technical constraints, which results in minimizing the repair volume in order to reduce manufacturing time and costs. Finally, repair tests are performed on ellipsoidal pre-machining, in order to observe the influence of the surface conditions and the pattern deposition on the final quality of the repair (porosity, microstructure and microhardness). The repaired parts highlight a heterogeneous microstructure and microhardness. The surface condition of the pre-machining has no influence on the repair. However, the deposition pattern influences the presence of porosities and the microhardness value in the deposit.