| Abstract | Laser cladding uses a focused laser beam to melt injected or pre-placed powder (or wire) to deposit a layer of desired material onto the surface of a substrate to form a dense and metallurgically sound coating with improved wear, corrosion and/or oxidation resistance. Compared to the conventional weld deposition, laser cladding induces much less heat input to the substrate and also produces a refined microstructure in the coating due to a relatively fast cooling inherent in the process. However, there is still certain amount of process induced residual stresses in the clad, which may adversely affect the mechanical properties and dimensional stability of the parts being clad. In this paper, a blown powder laser cladding technique was used to deposit high-vanadium CPM-9V and CPM-10V tool steel powders on AISI 1070 carbon steel substrate in order to improve its wear resistance. After the cladding, a series of heat treatments were performed on the clad specimens to alleviate the process induced residual stresses. The residual stresses were evaluated using a hole-drilling method. The evolution of the microstructure in the laser clad CPM-9V and CPM-10V coatings during the treatments was also examined using scanning electron microscope and X-ray diffraction. This study was performed to obtain a better understanding of the nature of the residual stresses in the laser clad CPM-9V and CPM-10V tool steel coatings. |
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