换热器管板角焊缝相控阵自动超声检测技术研究

Research on Phased Array Automatically Ultrasonic Testing Technique of Tube to Tube-sheet Welds in Heat Exchanger

在换热器的制作过程中,换热管与管板常采用焊接形式,焊缝的质量是保证换热器长期正常运行的关键。常规的超声检测方法具有系统复杂、检测效率低等缺点。因此,提出了相控阵超声检测技术,并开发了相控阵超声检测系统,以实现对管板角焊缝的自动超声检测。系统由周向步进电机实现周向扫查,纵向扫查采用相控阵探头电子线扫查,从而实现超声C扫描检测。通过带有气孔、未熔合等典型缺陷对检测系统进行试验研究。结果表明,该技术可以有效地检测出换热器管板角焊缝中的典型缺陷。

In the process of produce heat exchangers, heat exchanger＇s tube and tube sheet conjunction adopt the form of welding, the quality of welding is the key insurance for the long and normal operation of the heat exchangers. The conventional ultrasonic testing method has many disadvantages like complicated system and low efficiency of detection. Thus, it puts forward the phased array ultrasonic testing technique and develops the ultrasonic testing system to accomplish the automatically ultrasonic testing of the tube to tube-sheet welds. The ultrasonic C-scan was carried out by the ultrasonic testing system with its circumfer- ential scanning by a mechanical scanning device while the axial electronic linear scanning by the phased array probe. At last, the tests on samples with typical flaws such as porosity flaws and the incomplete fu- sion flaws were performed by the ultrasonic testing system. Experiment results showed that the phased ar- ray ultrasonic technique could effectively detect the typical flaws in the tube to tube-sheet welds of heat exchanger.