发生器头部电子束焊缝熔深相控阵超声检测

Phased array ultrasonic testing of electron beam weld penetration at generator head

为了解决液体火箭发动机燃气发生器头部关键电子束焊缝熔深无法测量问题开展相控阵超声检测技术研究。基于发生器头部焊接结构特点阐述了熔深测量原理;建立了超声仿真模型,对带有矩形槽人工缺陷的模拟件进行检测试验,验证了模型建立的合理性和计算结果的有效性;通过仿真分析获得了不同频率相控阵探头在工件内部的横波声场信息,对探头频率进行了优选;根据不同焊接熔深下未焊透界面回波幅值随聚焦深度的变化规律及熔深测量结果,得到了聚焦深度的最佳取值范围;利用发生器头部模拟样件进行检测试验并与金相测量值对比,结果表明,对于焊接厚度约11 mm的焊缝,使用10 MHz线阵探头,聚焦深度设置为8 mm时,熔深测量误差小于1 mm,满足工程定量需求。

In order to solve the problem of weld penetration measurement at the head of gas generator in liquid rocket engine,the phased array ultrasonic testing technology was studied.The principle of penetration measurement was described according to the welding structure characteristics of generator head.Through the inspection tests on the simulated parts with rectangular groove artificial defects,the rationality of the ultrasonic simulation model and the validity of the calculation results were verified.Transverse wave sound field information of phased array probes with different frequencies was obtained through simulation analysis,and the probe frequency was optimized.According to the variation of echo amplitude of incomplete penetration with the focus depth under different welding penetration depths and the measurement results,the optimal value range of the focus depth was obtained.The simulation specimen of the generator head was used for testing and compared with the metallographic measurements.The results show that for the weld thickness of about 11 mm,the measurement error of penetration is less than 1 mm compared with the metallographic value,when using 10 MHz linear phased array probe and focal depth is 8 mm,which meets the quantitative requirements of engineering.