搅拌摩擦焊技术在弹箭体贮箱锁底环缝上的应用

Application of Friction Stir Welding Technology to Lock Circumferential Weld of Launch Vehicle Tank

明确了搅拌摩擦焊技术应用于贮箱锁底环缝需要解决的关键问题。首先对熔焊锁底接头结构进行了搅拌摩擦焊工艺适应性设计,取消了背部焊漏槽和正面焊接坡口。结果表明:当叉形环位于焊缝前进侧,搅拌针长度与短壳板材厚度相当时锁底接头力学性能最优。锁底接头超声相控阵分析结果表明:存在于装配界面与焊核交界处的信号显示可以不当作缺陷信号判读。提出了采用立式帽装方式实现锁底环缝的装配焊接方案,并研制了可以保证锁底环缝装配间隙、错边、环缝平面度、贴合度以及叉形环大端周长的成套工装。实现了搅拌摩擦焊技术在Φ3 350 mm贮箱锁底环缝上的工程化应用,无损检测结果、形位尺寸符合设计要求。

This paper clarified the key problems in the application of the friction stir welding technology to the lock circumferential weld of the tank. Firstly, the conventional structure of the lock joint used to fusion welding must be redesigned, and the back welding groove and the front welding groove were eliminated. The results showed that the mechanical properties of the lock joint presented the best performance when the length of the pin was equal to the thickness of the short shell, and the fork ring was located on the advancing side of the weld. The results of ultrasonic phased array analysis showed that the signal display existing at the interface of assembly interface and welding nugget can not be interpreted as the defect signal. The vertical assembly welding scheme is used to assemble and weld the lock circumferential weld, and a set of tooling is developed to assure the assembly clearance, the wrong side, the flat- ness of the weld, and so on. The friction stir welding technology has been applied to the lock joint of the φ3350 mm tank has been realised, and its nondestructive test results and geometrical dimension met the design requirements.