Influence Of Water Layer On Water Immersion Ultrasonic Testing Of Steel Forgings

Water immersion ultrasonic testing technology of occupies an important position in the field of ultrasonic non-destructive testing.It has the characteristics of high signal-to-noise ratio,stable signal,good adaptability to curved components,high efficiency and easy to realize automation.In recent years,water immersion ultrasonic testing has developed rapidly and has a good application prospect.In this paper,according to the characteristics of water immersion flaw detection,the effect of water layer on flaw detection parameters in ultrasonic testing of steel forgings was studied.The influence of water layer on the attenuation of ultrasonic signals and the acoustic energy loss of water immersion flaws were analyzed.Finally,The focusing probe focus point and focused sound field are studied to adapt to the detection of different thickness workpieces.The main research results of this article are as follows:(1)Experiments were conducted to compare the experimental parameters of water immersion and water contact inspection,and the differences in signal-to-noise ratio between water-immersed focusing probes,water-immersed non-focusing probes and contact detection were analyzed.At the same time,ultrasonic sounding sensitivity and sensitivity were also examined.Parameters such as margin and gain are compared and analyzed.The results show that the parameters of water-immersion flaw detection of non-focus probes are lower than those of contact detection.The parameters of water-immersion flaw detection can be effectively improved by water-immersed focusing probes.The parameters of the water-immersed focusing probe flaw detection and contact flaw detection are not much different.(2)Analyze the factors affecting the attenuation of ultrasonic energy in ultrasonic testing.Combining with theory and experiment,this paper analyzes the acoustic energy loss of ultrasonic wave propagation in water during ultrasonic immersion ultrasonic flaw detection,and finds the cause of serious loss of acoustic energy caused by flooding inspection.The results show that the transmission and reflection of ultrasonic wave at the water-steel interface is the main cause of serious loss of acoustic energy,and acoustic energy loss formula is L=(?(1-?))/((1+?)~3).where?is the ratio of the acoustic impedance of the workpiece to the acoustic impedance of water.(3)The acoustic field characteristics of the water-immersed focusing probe were theoretically analyzed,the focusing point of the water-immersed focusing probe in water,the length of the coke column and the diameter of the coke column,the focus position of the water-immersed focusing probe in the workpiece were studied,and the position of the focused spot was analyzed for immersion ultrasonic inspection signal effect.Using the ball target method experiment,the sound field distributions of the 5MHz and 2.5 MHz probes in water were obtained.