球罐对接焊缝超声TOFD及超声相控阵检测实验研究

Experimental study on ultrasonic TOFD and ultrasonic phased array testing in butt weld of spherical tanks

对与球罐材质相近,厚度、坡口形式和焊接工艺相同定制的对接焊缝试块,利用超声衍射时差法(TOFD)检测技术和超声相控阵检测技术进行检测,分析比较两种方法的检测结果.实验结果表明,超声TOFD检测可以高效和精确地检测出焊缝中的缺陷,但它存在近表面和近底面盲区;超声相控阵检测可以借助探头声束的聚焦和可转向的特点,检测出焊缝近表面和近底面的缺陷.因此,将两种检测方法结合使用,可以有效提高焊缝近表面检测效果,提高缺陷的检出率,实现缺陷的精确定位和定量.

The ultrasonic TOFD detection technology and ultrasonic phased array inspection technology were used in the testing of the customized butt weld block of similar spherical tank material and the same thickness, groove form and the welding technology. The test results of the two methods were analyzed and compared. The experimental results showed that the ultrasonic TOFD was able to detect the weld defects efficiently and accurately. But it had a blind area near the surface and the bottom. Ultrasonic phased array inspection could detect the defects in the weld near the surface and the bottom by the characteristics of the probe beam＇s focusing and steering. A combination of the two kinds of detection methods could effectively improve the effect of the weld detection near the surface and raise the defect detection rate with precise defects location and quantitative evaluation.