Ultrasonic time-of-flight diffraction (TOFD) detection method for weld seam

A detection method, ultrasonic technology, applied in the analysis of solids using sound waves/ultrasonic waves/infrasonic waves, material analysis using sound waves/ultrasonic waves/infrasonic waves, and measuring devices. Wide range of effects

Inactive Publication Date: 2012-06-20
STATE GRID HEBEI ENERGY TECH SERVICE CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] However, for the butt welds between pressure pipes and special-shaped components such as elbows, elbows or tees, due to the structure of the base metal on both sides of

Method used

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  • Ultrasonic time-of-flight diffraction (TOFD) detection method for weld seam
  • Ultrasonic time-of-flight diffraction (TOFD) detection method for weld seam
  • Ultrasonic time-of-flight diffraction (TOFD) detection method for weld seam

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Embodiment Construction

[0014] Such as figure 1 As shown, the probes of the conventional TOFD detection technology are placed on both sides of the weld, and it cannot detect the butt welds of pressure pipes and special-shaped components such as elbows, big and small heads or tees. Such as figure 2 Shown is a schematic diagram of the probe layout of the method of the present invention, the receiving probe 1 selects a probe with a large refraction angle (60 degrees), and the transmitting probe 2 selects a probe with a small refraction angle (20 degrees); in order to ensure that the ultrasonic waves can cover the weld seam to the greatest extent The region can obtain as high a signal-to-noise ratio as possible, and the distance L between the probe spacing PCS and the center line of the transmitting probe 2 and the weld 4 is determined according to the thickness of the workpiece and the angle of the probe; the above-mentioned two probes are installed on the scanning frame 12, and Connect with the TOFD ...

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Abstract

The invention relates to an ultrasonic time-of-flight diffraction (TOFD) detection method for a weld seam. The ultrasonic TOFD detection method comprises the following steps of: respectively taking two probes with different refraction angles as a transmitting probe and a receiving probe; arranging the transmitting probe and the receiving probe at the same side of the weld seam; connecting the transmitting probe and the receiving probe with a TOFD instrument; scanning the weld seam; carrying out interpretation on scanned images; finishing the scanning if no defected signal images are discovered; if defected signal images are discovered, changing probe clearance space (PCS), keeping the other settings and parameters unchanged, and carrying out scanning once again; calculating according to two-time scanned results; and achieving the positioned and quantitative detection of the defects of the weld seam. According to the ultrasonic TOFD detection method, a single-face one-sided scanning manner is adopted, the original advantages of TOFD detection are kept, meanwhile, the TOFD detection for the butt-jointed weld seams between a tube body of a pressure vessel and an end enclosure as well as between a pressure conduit and irregular members, such as an elbow, a pipe reducer or a tee joint and the like, is achieved, and thus, the ultrasonic TOFD detection method is wide in scope of application.

Description

technical field [0001] The invention relates to an ultrasonic time-of-flight diffraction detection method for weld seams. technical background [0002] In the early 1970s, Dr. Smith Kline invented the ultrasonic time-of-flight diffraction detection (TOFD) technology. TOFD technology is a crack size detection technology, which consists of two probes, one for transmitting and the other for receiving. The principle is to calculate the position of the crack by re-emitting energy after ultrasonic diffraction. Compared with conventional pulse echo technology, TOFD technology has two biggest advantages: 1. It has high quantitative accuracy, and the absolute error is plus or minus one millimeter; 2. It is not sensitive to the angle of defects during the detection process , quantification is based on the time of the diffracted signal rather than the amplitude of the signal. At present, for the conventional TOFD detection of welds, the TOFD probes need to be placed on both sides of ...

Claims

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Application Information

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IPC IPC(8): G01N29/04G01N29/265
Inventor 赵纪峰郝晓军牛晓光李中伟刘长福
Owner STATE GRID HEBEI ENERGY TECH SERVICE CO LTD
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