Time-of-flight diffraction ultrasonics

About: Time-of-flight diffraction ultrasonics is a research topic. Over the lifetime, 544 publications have been published within this topic receiving 3189 citations.

Compound probe for detecting defects of weld joints of workpieces

Abstract: The utility model discloses a compound probe for detecting defects of weld joints of workpieces. The compound probe comprises a long cylindrical shell. An organic glass wedge is arranged in the middle of the shell, a damping block is arranged on the periphery of the organic glass wedge and is positioned in the shell, an inclined TOFD (time of flight diffraction) chip, a common pulse reflection ultrasonic chip a and a common pulse reflection ultrasonic chip b are sequentially inlaid on the organic glass wedge from the right end to the left end of the organic glass wedge, and a power line and a power line port which are used for being connected with a piezoelectric chip are arranged at the left end of the shell. The TOFD chip and the common pulse reflection ultrasonic chips are combined to form the TOFD and common pulse reflection ultrasonic compound probe, the interlayer defects of the weld joints are accurately positioned by the TOFD chip, regions of upper and lower surfaces of the weld joints are detected by a common pulse reflection ultrasonic probe, and the problem of surface 'dead zones' in the TOFD detection technology can be solved.

Method for reducing near surface blind region in TOFD (Time of Flight Diffraction) detection based on spectral analysis principle

Abstract: The invention discloses a method for reducing a near surface blind region in TOFD (Time of Flight Diffraction) detection based on a spectral analysis principle, belonging to the technical field of ultrasonic non-destructive test. The method is completed by virtue of one set of ultrasonic testing system comprising a TOFD ultrasonic detector, a computer integrating TOFD operating software, a TOFD probe, a scanning device, a calibration test block and a digital oscilloscope. A near surface region in the TOFD detection is scanned, an acquired aliasing time-domain signal including defect information is subjected to spectral analysis, a resonant frequency in an amplitude spectrum is read, a sonic path difference between a direct-through wave and a tip diffracted wave on a defect is figured out in combination with a material longitudinal wave velocity, and the defect burial depth in the near surface blind region is further determined. Compared with other methods for reducing the depth of the near surface blind region, the method has no extra requirements on a hardware system, is not limited by thickness of a to-be-tested workpiece, and has good engineering application value.

Analysis of Wave Propagation for the TOFD Method by Finite Element Method: Optimization of Test Configuration and Proposal of a New TOFD Method

Abstract: Wave propagation in an austenitic stainless steel specimen with a slit open to the lower surface is modeled using finite element method, with consideration of the effects of scattering at grain boundaries. The distribution of energy of a diffracted longitudinal wave shows that this wave has the strongest energy directly above the slit. As a consequence of this result, a new testing method is proposed. The new method is verified using austenitic stainless steel specimens. Experimental results show that the new method is applicable to austenitic stainless steel with high accuracy, to which the time of flight diffraction method (TOFD) is not applicable.

Automatic ultrasonic flaw detection method and device

Abstract: PROBLEM TO BE SOLVED: To obtain an automatic ultrasonic flaw-detecting device for simultaneously detecting the flaw of a base material welded part and a padding welded part. SOLUTION: Ultrasonic fly detection by TOFD method and that by PA method are simultaneously conducted on a welded joint part 10. In the PA method, an array probe 21 where a number of vibrators for receiving ultrasonic waves are arranged linearly in the width direction of the welded joint part 10 is used for detecting the flaw of a padding welded part 11 and a base material welded part 12. In the TOFD method, two pairs of transmission and reception probes provided adjacent to the array probe 21 and across the padding welded part are used for performing the ultrasonic flaw detection of the base material welded part.