Study On Ultrasonic Testing For Transverse Crack In T23 Steel Water Wall Tube

T23 steel boiler water wall is widely used in nuclear power and thermal power industries.The quality of welds on water wall has a direct influence on security ofboilers and its system in service.Due to field conditions and the position of defects,transverse cracks located on welds of T23 steel boiler water wall tubes are hard to detect.This paper,on the premise of not dealing with the weld height,aiming to discuss the ultrasonic testing of transverse cracks located on welds of boiler water wall tubes,had conducted a series of beneficial explorations through a variety of methods of ultrasonic testing for transverse crack in weld(oblique parallel scanning method,double probe cross weld detection method and TOFD method),in order to explore the applicable and reliable engineering ultrasonic detection method of water wall tube of the in-service boiler.Through the simulation and experimental study of various detection methods,it has been proved that the double probe method has higher detection sensitivity and detection accuracy,and its effect is better than the other two methods.The imaging of double probe cross-weld scanning has been realized,and the best detection eccentricity range is 40-50 degrees,based on which the 3D model of special testing probe wedge was figured.