高级检索

奥氏体不锈钢焊缝超声阵列检测方法

Nondestructive testing of austenitic welds using method of ultrasonic array

  • 摘要: 在焊接热循环作用下,奥氏体不锈钢焊缝内部呈粗大柱状晶组织,且其取向在焊缝不同区域呈各向异性.针对粗大柱状晶引起的超声波散射和晶粒取向不同导致的声束偏折等问题,进行奥氏体不锈钢焊缝超声阵列检测方法研究.针对超声阵列获得全矩阵数据,发展了一种基于时间反转算子分解的超声阵列信号去噪方法.利用射线追踪法,研究了各向异性介质中超声波传播路径确定方法,并将其应用于奥氏体不锈钢焊缝超声阵列全聚焦成像的声束偏折校正.开展了奥氏体不锈钢焊缝超声阵列检测试验研究.结果表明,基于时间反转算子分解方法可以很好剔除检测信号中的散射噪声,凸显特征回波信息,可将全聚焦成像的信噪比提高10 dB,而波束偏折校正则可以提高超声阵列全聚焦成像中缺陷定位的精度.

     

    Abstract: Under the action of welding thermal cyclic load, the internal peritectic structure of austenitic stainless steel weld is coarse columnar crystal, and its orientation is anisotropic in different areas of the weld. The nondestructive testing of austenitic stainless steel welds is conducted using method of ultrasonic array for the ultrasonic scattering caused by coarse columnar crystals and the sound beam deflection caused by different grain orientations. A signal analysis method based on decomposition of the time-reversal operator is developed for noise reduction processing of ultrasound full matrix data. Using ray tracing method, the ultrasonic wave propagation path determination method in anisotropic media was investigated and applied to the correction of beam deflection for ultrasonic array total focus imaging of austenitic stainless steel welds. Nondestructive testing of austenitic stainless steel welds was conducted using ultrasonic array, and the results showed that the time-reversal operator-based decomposition method was effective for the suppression of scattering noise in the detection signal and highlight the echoes from defects, which can improve the signal-to-noise ratio of full-focus imaging by 10 dB, moreover the beam deflection correction can improve the accuracy of defect localization in total focus imaging of ultrasonic arrays.

     

/

返回文章
返回