Investigation on influence of thermal history on quality of workpiece created by directed energy deposition

The effects of thermal history on workpiece hardness and cracking in the cladding of M2 high speed steel were investigated through the combination of numerical and experimental techniques. A simple thermal model was developed to simulate the workpiece temperature in the deposition. The obtained results showed that the workpiece temperature should be kept above the martensitic transformation point by continuously applying heat to avoid cracking and temper softening. The simplified temperature simulation in this study is effective for the deposition path strategy because it was able to predict where the temper softening would occur.