搅拌摩擦焊焊缝缺陷的超声相控阵检测技术

Ultrasonic phased array inspection technology for defects in friction stir welded seam

关键词:  铝合金  搅拌摩擦焊  超声相控阵  焊接缺陷

Key words:  aluminium alloy  friction stir welding  ultrasonic phased array  weld defect

摘要:

采用超声相控阵技术对不同厚度铝合金搅拌摩擦焊焊缝的缺陷进行了探测,通过改变相控阵的扫描角度、聚焦深度、焦点尺寸等参数对焊缝内部缺陷进行了准确定量和图像再现,并对缺陷信号标记部位进行了解剖、观察了缺陷的宏观形貌.结果表明,探头检测灵敏度高,易于快速分辨焊缝内部缺陷,结合不同的扫查方式直观给出缺陷三向视图,可准确定位缺陷的位置、尺寸、分布;缺陷形状直接影响回波的形状和峰值,小孔洞为单一尖锐波峰,峰值高大;包铝层和疏松由多簇波峰构成,S显示疏松亮点比包铝层密集且分布面较大.

Abstract:

Ultrasonic phased array inspection technology was used to detect the defects in friction stir welded seam with different thicknesss. The inner defects were precisely quantified and represented by changing the scanning angle,focus depth and focus size of phased array. The morphology of the defects was observed by dissecting the welded seam with defect signal. The results show that the inner defects can be quickly determined with higher detection sensitivity probe. The position,size and distribution of the defects can be precisely detected through three views obtained by different scanning modes. The shape and peak value of echo signal were determined by the defect shape. The echo signal of little hole defect was a sharp peak and the peak value was large. The echo signals of aluminium coating and loose defects were multiple-cluster wave. In S-scan,the lightspots of loose defect were more intensive and distributed more widely than aluminium coating defect.