基于超声环阵相控阵的变孔径聚焦检测技术

Vari-aperture Focusing Inspection Technique Based on Ultrasonic Annular Phased Array

超声相控阵检测技术在检测效率方面的优势,使其有望取代分区聚焦检测法而用于粉末高温合金盘件的缺陷检测。为了解决超声相控阵检测在焦点尺寸控制、灵敏度一致性和近表面分辨力等方面的问题,采用模拟试验和试验验证的手段研究粉末涡轮盘的超声相控阵检测技术,提出变孔径超声相控阵聚焦检测方法。结果表明:该方法可使检测灵敏度的一致性由5 dB优化至3 dB,近表面分辨力减小到3.2 mm;与传统的分区聚焦检测方法比较的结果表明,采用本方法具有与分区聚焦检测接近的缺陷检出能力,同时可将检测时间缩短至原来的1/4。

Ultrasonic annular phased array has the potential to replace multi-zone focusing ultrasonic technique(UT) for the inspection of powder metallurgical(PM) turbine disks due to the advantage of efficiency and high sensitivity. The present work investigated the ultrasonic phased array inspection technique for PM turbine disks by simulation and experimental verification,in order to solve the problems of focal size control,sensitivity consistence and near-surface resolution. Vari-aperture focusing inspection technique was put forward on the basis of annular phased array ultrasonic focus theory. With the technique in the present work,the sensitivity consistence was optimized from 5 dB to 3 dB,and near-surface resolution reduced to 3.2 mm. Compared to conventional multi-zone focusing UT,the present technique has similar defects detection capability,while the time consumption reduces by 3/4.