不同焊接热循环状态隔离层对再焊接环缝组织和性能的影响

Effect of Insulating Layer with Different Welding Thermal Cycle States on Microstructure and Properties of Rewelding Ring Joints

核电主设备安全端的质量直接影响整个核电系统的安全,出现缺陷一般采用手工焊局部修复,难以满足第三代核电技术的要求。在“华龙一号”核电主设备安全端修复过程中,首次采取对整个安全端切除并通过全位置凸台熔敷和窄间隙焊接技术对安全端进行了成功修复。通过对再制造过程中不同焊接热循环状态下的隔离层进行模拟试验,发现留存部分原镍基环缝的焊缝性能优于完全去除原镍基环缝的焊缝,并对其进行了力学性能测试、无损检测和金相组织分析。研究结果表明,部分保留原镍基环缝可有效改善焊缝性能,其晶粒更加细小,方向性更加明显。力学性能和液体渗透、超声波探伤等无损检测均未发现相关缺陷。这一发现为核电主设备安全端修复提供了重要参考,进一步推动了核电设备再制造技术的发展。

The quality of the safety end in nuclear power main equipment directly affects the safety of the entire system.And defects were generally repaired locally by manual welding,which was difficult to meet the requirements of the thirdgeneration nuclear power technology.In the process of repairing the safe end in the nuclear power equipmen(HPR1000),the entire safe end was removed for the first time and successfully repaired through all-position boss cladding and narrow gap welding technology.Moreover,the buttering layer of different welding thermal cycle states in the remanufacturing process was studied,and the physical and chemical properties of the corresponding repair simulation parts were tested.The results showed that the mechanical properties of the repaired simulated parts were tested for tensile,impact,bending,and which fully met the requirements.Meanwhile,no related defects were found in non-destructive testing(PT and UT)of the welded simulated parts.Finally,the microstructure and grain size were tested and analyzed,the microstructure of weld was coincident and meliorative.The successful repair of the safety end further promotes the development of remanufacturing technology nuclear power equipment.