手持激光填丝焊接技术修复超高压输电线路金具的工艺研究

Research on Hand-Held Filling Wire Laser Welding Repair of Metal Fittings Used in Extra-High Voltage Power Transmission

摘要:

激光焊接具有优良的焊接质量和高效率，已在部分行业替代传统的电弧焊接工艺，而手持激光焊接技术的开发提升了作业灵活性，大幅增加了工业领域的接受程度。为进一步提高超高压输电线路用铝合金金具的修复水平，研究了手持激光焊技术的修复可行性，考察了激光功率、光束摆动模式和幅度等参数对修复效果及形貌的影响，同时测试了修复接头相应的抗拉强度、导电性。研究结果表明：采用手持激光焊接修复技术，在光束为“—”摆动模式下可获得成形良好的修复层，修复层存在多道次组织特征，焊缝中间的晶粒较小，靠近母材处晶粒较大；在合适的激光功率、摆动幅度范围内，线性修补能够一次性实现对细小裂纹类线性缺口的修复且效果显著，修复接头的抗拉强度不低于母材、导电性可达到母材的89.43%、硬度高于母材。综上，采用手持激光填丝焊接可实现铝合金输电金具的修复，有望用于超高压输电线路金具缺口的修复。

关键词:铝合金金具;手持激光焊接;修复工艺;超高压输电

Abstract:

Laser welding has excellent welding quality and high efficiency， and has partly replaced the traditional arc welding process. The development of hand-held laser welding technology improves the flexibility of operation， therefore greatly increasing its industrial acceptance. To further improve the repair level of aluminum alloy fittings for ultra-high voltage transmission lines， the repair feasibility of hand-held laser welding technology was studied， the influence of parameters such as laser power， beam swing mode， and swing amplitude on the repair effect and morphology were studied， and the tensile strength and electrical conductivity of respective repaired joints were tested. Results show that using the hand-held laser welding technology， a well-formed repair layer can be obtained when the beam is in the "—" swing mode. There are multi-pass microstructure characteristics in the repair layer， and the grains in the middle of the weld are relatively small， and the grains near the base metal are larger. With appropriate range of laser power and swing amplitude， linear repair can well repair small crack-like linear gaps at one time. The tensile strength of the repaired joint is not lower than that of the base metal， and the electrical conductivity can reach 89.43% of the base metal， and the hardness is higher than that of the base metal. In summary， the use of hand-held laser wire filling welding can realize the repair of aluminum alloy power transmission fittings， and it reveals significant prospects to be used for repairing gaps in ultra-high voltage transmission line fittings.

Key words:aluminum alloy fitting;hand-held laser welding;repair technology;extra-high voltage power transmission