复杂结构焊缝缺陷双线阵全聚焦超声成像方法

Dual-linear-array TFM ultrasonic imaging method for weld defects of complex structure

某型航空发动机高温合金盘由涡轮盘本体和外层整体叶片环焊接而成,采用常规单通道超声方法检测焊接面缺陷时,存在检测分辨率低、信噪比差等问题,为此,提出了一种采用两组线性阵列换能器的检测方案。利用全聚焦方法(TFM)对焊接面缺陷进行成像表征,与常规全聚焦方法不同,阵列孔径和波形模式均能随检测深度动态变化,其最优参数通过理论仿真确定。制备了含预埋缺陷的航空发动机高温合金盘试样,开展了检测实验。结果表明:提出的双线阵全聚焦超声成像方法能有效提高高温合金盘未焊合面积型缺陷的检测能力,是一种可行的检测方案。

A certain type of superalloy disk component of aero-engine is welded by the turbine disk and the outer integral blade ring,and when the conventional single-channel ultrasonic method is used to detect welding surface defects,there are problems such as low detection resolution and poor signal-to-noise ratio.For this reason,a detection scheme using dual-linear-array transducer is proposed.The Total Focusing Method(TFM)is used to image and characterize welding surface defects.Unlike the conventional TFM,the array aperture and waveform pattern can be dynamically changed with the detection depth,and the optimal parameters are determined by theoretical simulation.Samples of aero-engine superalloy disk with embedded defects were prepared,and testing experiments were carried out.The results show that the proposed dual-linear-array TFM ultrasonic imaging method can effectively improve the detection ability of unwelded area defects in superalloy disk and is a feasible detection scheme.