Research On Ultrasonic Phased Array Testing Technology Of U Rib Fillet Weld

The bridge deck as the main body of the domestic steel structure bridge bears great pressure.After long operation, the fatigue damage of the bridge panel and U rib is serious. The requirements of design and specification about the penetration depth of the bridge deck and U rib fillet weld is not less than 75%U rib thickness.In view of this specification, the test plate of the U rib fillet weld is used, by physical macrographic test to judge the welding process, In production process, by visual inspection and magnetic testing at the two ends. And whether the actual weld quality meets the requirements is not detected.In view of this situation, the application of ultrasonic phased array technology in the production process of the solid weld inspection and evaluation is presented in this paper.Using 16 wafer 7.5MHzsegment frontier phased array probe, image quality is better, but different signal reading method of penetration measurements have obvious difference, take effective end point signal reading method on penetration was assessed with minimum error. U rib weld seam detection data of physical macroscopic anatomy as true value, research on the reliability of the detection of the ultrasonic phased array technology, the results show that the phased array detection data than ordinary A detection data dispersion.In 95% confidence, the weld penetration of phased array measurement data(A) with probability 95% is in the range of(A-0.066, A+0.066).U rib root weld forming shape can be roughly divided into four types, the root of slag or gap, lack of penetrationin bridge deck side, lack of fusionin U side groove hot crack of positioning welding. In order to improve the accuracy of the test data in detection process, select the measurement according to the signal display.U rib thickness affect the detection results. In the detection process, measure the thickness actual, and input parameters thickness value cannot be less than the actual thickness.Under the same process using ultrasonic phased array equipment from different manufacturers were detected, although there are some differences between the data, but its scattered little, show that different manufacturers of phased array equipment can effectively detection for U rib weld penetration. The internal defect of U rib weld can be evaluated according to the GB11345 equivalent method, also can be evaluated lack of penetration depth in the production process, to improve the detection efficiency.Design and productionof semi automatic scan device of u rib weld detection, in laboratory conditions, can be used to detection of U rib welds, and the data can reproduce. But in factory testing conditions, the possibility of error data is larger to using semi automatic scan device, need to redesign and improvement. Measurement data using direct method and a reflection method can coincide with each other, and in the actual test to determine the detection method according to the site condition. On the basis of the above research, Ultrasonic phased array inspection technology, has completed the actual project U rib weld penetration depth measurement 163600, of which 177 are not up to the standard. To provide effective guarantee for the quality of the welding seam of the bridge...