Degradation Repairing of the Decayed Alloy 82 Weldment by LSM
碩士 === 國立成功大學 === 機械工程學系碩博士班 === 100 === The Intergranular Corrosion (IGC) and Interdendritic Corrosion (IDC) cracking often happened in the nickel based alloy weldment of nuclear power plants. Laser Surface Melting (LSM) was employed to repair the decayed Alloy 82 weldment. This study concerned n...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2012
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| Online Access: | http://ndltd.ncl.edu.tw/handle/23830065560091227291 |
| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 100 === The Intergranular Corrosion (IGC) and Interdendritic Corrosion (IDC) cracking often happened in the nickel based alloy weldment of nuclear power plants. Laser Surface Melting (LSM) was employed to repair the decayed Alloy 82 weldment. This study concerned not only the corrosion resistance, but also the residual stress caused under different laser processing parameters. The IGC and IGSCC susceptibility of the repaired area were evaluated by the Modified Huey test and Bent-Beam Stress Corrosion Test. Hole-Drilling Method was used to measure the residual stress before and after LSM process.
The experimental results showed that the microstructure with refined sub-grain in laser melted zone showed excellent IGC, IDC and IGSCC resistance. No crack formed in laser melted zone where Nb-rich phase and chromium carbide were resolved and redistributed. The decayed alloy 82 cladding was rejuvenated and corrosion resistance was recovered. The residual stress measurement result indicated that LSM with pulse laser induced lower residual tensile stress. The inner layer of laser melted parts produced residual compressive residual stress. Laser Surface Melting was proven to be a practical technique for repairing the decayed Alloy 82 weldment.
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