Ultrasonic detection method for weld joint of small-caliber pipe shelf angle

Abstract

The invention provides an ultrasonic detection method for a weld joint of a small-caliber pipe shelf angle. A digital ultrasonic fault detector is adopted to calculate and determine the refraction angle of a probe utilizing the formula that beta is equal to or larger than tan<-1>[(H+L0) / 2T] according to weld joints of pipe shelf angles in various specifications, so that the acoustic beam axis of the primary reflection wave can reach the end part of a pipe adapter, wherein H is the sum of the weld joint of the shelf angle, the depth of a header groove and the insertion depth of the pipe adapter, and T is the wall thickness of the pipe adapter; a monocrystal transverse wave angle probe with a corresponding refraction angle is adopted for detection from the outer side of the pipe shelf, so that a defect at the root part of the welt joint of the shelf angle can be effectively detected, a defect wave and structural wave can be accurately identified, missed detection and wrong detection during the detection of the workpieces can be reduced, and the accuracy of the detection work can be greatly improved.

Description

technical field [0001] The invention relates to an ultrasonic welding seam detection method, in particular to the detection of the internal quality of the fillet weld (in the form of incomplete penetration) of small-diameter tube bases such as boiler headers. Background technique [0002] Nowadays, when the conventional ultrasonic testing method is used to test the fillet weld of the small-diameter pipe seat of the unpenetrated structure, the insertion part of the pipe has an unpenetrated gap at the root of the fillet weld, which is equivalent to the existence of a pipe at the root of the weld. This end produces more inherent echo signals in conventional ultrasonic testing, which has a great impact on the judgment of normal defect echoes, resulting in missed detection and false detection of workpieces. An ultrasonic testing method and inspection standard for fillet welds (incomplete penetration form) of plug-in small diameter sockets. SUMMARY OF THE INVENTION [0003] In ...

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Problems solved by technology

[0002] Nowadays, when the conventional ultrasonic testing method is used to detect the fillet weld of the small-diameter pipe seat of the impermeable structure, the insertion part of the pipe has an unpenetrated gap at the root of the fillet weld, which is equivalent to the existence of a pipe at the root of the weld. The terminal, which produces more inherent echo signals in conventional ultrasonic testing, has a great impact on the judgment of normal defect echoes, resulting in missed and false detections of workpieces. So far, there is no An ultrasonic detection method and inspection standard for fillet welds (non-penetration form) of plug-in small-diameter pipe sockets

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