核电厂稳压器电加热器在役更换自动焊接技术

摘要

In order to fill the domestic technology gaps and improve the capability of self-maintenance of main equipment in nuclear power plants,the automatic welding technology for replacing in-service heater elements of voltage stabilizer is researched.According to the characteristics of replacing in-service electric heater and the shortcomings of existing technology,the closed welding head is developed,which improves the stability of welding arc and gas shielded effect.Through a large number of automatic welding technology tests,the influence of protective atmosphere,specimen size and the chemical composition of base metal on the appearance of weld are discussed,and the welding parameters are determined.The results show that the use of argon backside protection and helium front protection welding can ensure complete penetration and protective effect on backing pass;the deviation of specimen structure size can affect the appearance of weld due to different heat dissipation;and the higher the content of S in the base metal chemical composition,the easier it is to penetrate.%为填补国内技术空白,提高核电厂主设备的自主维修能力,研究稳压器电加热器在役更换自动焊接成套技术.根据电加热器在役更换的特点及现有技术缺点,研发封闭式机头,提高焊接电弧的稳定性及气体保护效果.通过大量的自动焊接工艺试验,探讨保护气体、试件尺寸、母材化学成分等对焊缝成形的影响,确定焊接工艺参数.试验结果表明,采用氩气背面保护、氦气正面保护焊接既能保证焊透,又能保证背部保护效果;试件结构尺寸的偏差会因散热不同而影响焊缝成形;母材化学成分中w(S)越高则越容易焊透.