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0Cr17Ni4Cu4Nb powder was used to investigate the same-stuff laser repair(LR)technology on the semishrounded impeller.To improve the repaired effect,heat treatment was used after LR forming process.By means of optical microscopy,scan electron microscopy(SEM),micro-hardness tester and tensile tests,the microstructure of the coating was investigated and mechanical properties were measured.The experimental results show that cladding layer is well bonded to the substrate,the microstructure of the laser repaired zone(LRZ)is coarse martensite which will be refined after heat-treatment.The mechanical property experiments indicate that the micro-hardness and toughness would be increased after heat-treatment,the strength of LRZ after heat-treatment is 1050～1200 MPa,while the strength of normal laser repaired sample is 1000～1050 MPa.The refinement effect due to the heat treatment plays an important role in the improvement of the mechanical properties of samples.Overspeed examination and the real operation of the impeller after repairing also confirmed the reliability of this same-stuff and equal-strength laser cladding technology.
0Cr17Ni4Cu4Nb powder was used to investigate the same-stuff laser repair (LR) technology on the semishrounded impeller. To improve the repaired effect, heat treatment was used after LR forming process. By means of optical microscopy, scan electron microscopy (SEM), micro The hardness results and tensile tests, the microstructure of the coating was investigated and mechanical properties were measured. The experimental results show that cladding layer is well bonded to the substrate, the microstructure of the laser repaired zone (LRZ) is coarse martensite which will be refined after heat-treatment. The mechanical property experiments indicate that the micro-hardness and toughness would be increased after heat-treatment, the strength of LRZ after heat-treatment is 1050 ~ 1200 MPa, while the strength of normal laser repaired sample is 1000 ~ 1050 MPa. The refinement effect due to the heat treatment plays an important role in the improvement of the mechanical properties of samples. Overspeed examination and the r eal operation of the impeller after repairing also confirmed the reliability of this same-stuff and equal-strength laser cladding technology.