厚壁焊缝阵列超声SH波检测的成像方法

Imaging of Ultrasonic SH Wave Inspection of Thick-walled Welds Based on Array Technology

采用超声水平剪切SH波检测粗晶材料厚壁钢板内的2mm人工缺陷横孔并对其聚焦成像。搭建了20通道阵列超声SH波检测成像试验系统,检测待检的奥氏体不锈钢试样内部竖直排布的13个间距30mm±1mm,深度范围10～380mm,尺寸小于检测波波长(3.09mm)的人工缺陷。基于合成孔径聚焦原理对各通道信号处理并成像,准确定位了缺陷中心,并以一个检测波长以内的误差表征了缺陷大小。为高温高压下工作的钢制大型设备的焊缝在线检测提供了依据。

φ2 artificial defects in a thick walled scorched steel plate were detected and imaged with focused ultrasonic shear horizontal （ SH ） waves. An inspection and imaging system with 20 channels of ultrasonic shear horizontal waves was developed on the purpose of detecting the thirteen defects, being spaced out 30 ± 1 mm apart and ranged vertically within 10~380 mm deep, with the dimensions less than one detection wavelength（ 3.09 mm）. On the theory of synthetic aperture focusing for long distance inspections, the signals from the related channels were processed and imaged. It was achieved that the defects were accurately located, keeping the error range of dimensions no more than one detection wavelength. The method provides reference to the in-line detection of large scale steel equipments in high-temperature and pressure environment.