核用小直径传热管衬管焊接TIG焊枪的设计及优化

Design and Optimization of Liner TIG Welding Gun for Nuclear Heat Transfer Tube with Small Diameter

随着我国核工业进入第3个30年发展阶段,核用设备的维修需求日益迫切。核用蒸汽发生器内部结构复杂,关键传热管结构管径小、管道长、拆卸安装难度大,传统修复方法难度极高。针对核用小直径传热管因长期处于高温高压工况而出现的腐蚀破坏问题,文中设计了一种全位置自动化TIG衬管焊接修复焊枪,并进行了焊枪可靠性验证和焊接修复试验。首先,提出了焊枪的总体结构设计方案,并阐述了所设计焊枪相对传统钨极TIG焊枪的优势;接着,完成了焊枪传动系统的设计与验证,所设计的传动系统体积小、空间利用率高;随后,对焊枪关键部位——导电轴进行了刚度理论建模、分析和实例计算,并通过有限元求解验证了理论模型的可靠性,在此基础上提出了焊枪结构的优化方法;最后,进行了现场挠度检测和焊接试验,验证了导电轴的刚度满足现场焊接工况,并用线性回归方程和挠度修正公式定量预测焊枪挠度变形,验证了所设计结构的合理性;焊接试验表明焊枪工作时传动系统的转速稳定可控,焊缝成形良好。文中所研制的焊枪能够满足核用蒸汽发生器不锈钢传热管的衬管焊接修复工艺要求。

As China’s nuclear industry enters the third 30 years of development,the maintenance need for nuclear equipment is becoming increasingly urgent.The internal structure of the nuclear steam generator is complex,and the key structure,namely the heat transfer tube,has the restrictions like small diameter,long pipeline and difficult disassembly and installation,which make traditional repair methods extremely difficult in implementation.In order to solve the problem of corrosion damage of small-diameter nuclear heat transfer tube due to long-term high tempera⁃ture and high pressure condition,an all-position automatic TIG welding gun for liner repair was designed in this pa⁃per,and the gun reliability verification and welding repair test were carried out.Firstly,the overall structure design of the welding gun was presented,and the advantages of the designed welding gun comparing with the traditional tungsten electrode TIG welding gun were described.Next,the design and verification of the welding gun transmis⁃sion system with small size and high space utilization were completed.Then,the stiffness of the key part of the welding gun,namely the conductive shaft,was modelled,analyzed and calculated,and the reliability of the theoreti⁃cal model was verified by finite element solution.On this basis,an optimization method of the welding gun structure was proposed.Moreover,the field test of deflection and the welding test were carried out,finding that the stiffness of the conductive shaft satisfies the field welding conditions.Finally,linear regression equations and deflection cor⁃rection formulas were used to quantitatively predict the deflection of the welding gun,and the results verify the ratio⁃nality of the designed structure.Welding tests results show that the rotation speed of the transmission system is stable and controllable in working condition of welding gun,and the welding seam is well formed.The developed liner welding gun can satisfy the requirements of liner welding repair of the stainless-steel heat transfer tube inside the nuclear steam generator.