Ultrasonic detection method for defects at middle parts of welding seams of extra-large wall thickness SAWH steel pipe

Abstract

The invention discloses an ultrasonic detection method for defects at the middle parts of welding seams of an extra-large wall thickness SAWH steel pipe and relates to the technical field of ultrasonic flaw detection devices or methods. The ultrasonic detection method comprises the following steps: manufacturing artificial defects on the upper sides and the lower sides of the welding seams; respectively clamping one ultrasonic detection probe on the outer wall of a steel pipe on each of the left sides and the right sides of the welding seams, adjusting the distances from the probes to an upper side vertical hole or a lower side vertical hole well, slightly adjusting the probes and finding out defect reflection highest waves through an ultrasonic flaw detector; calibrating the ultrasonic flaw detector according to the reflection highest waves; detecting the welding seams of the steel pipe in batches by using the calibrated ultrasonic flaw detector. With the adoption of the method, the possibility of missing detection of defects in the middle region of the welding seams can be effectively reduced, the detection completeness of the steel pipe welding seams is improved, the missing detection probability of welding seams is reduced and the ex factory pass rate of the steel pipe is guaranteed, so that the product quality is improved.

Description

technical field [0001] The invention relates to the technical field of ultrasonic flaw detection devices or methods, in particular to an ultrasonic detection method for defects in the middle of a super-thickness SAWH steel pipe weld seam. Background technique [0002] After the third line of the West-East Gas Pipeline Project started production, the spiral seam submerged arc welded steel pipes have been using large-diameter pipelines with a maximum wall thickness of 18.4mm. Due to the development of the domestic economy, the consumption of natural gas is also increasing year by year. Several existing domestic The transmission pipeline has gradually been unable to meet the needs of industry, agriculture and household use. It is bound to require greater pressure and the manufacture and use of more pipeline projects. Under the premise of increasing the transmission volume, the diameter and wall thickness of the steel pipe will also increase. The increase means that spiral subme...

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Problems solved by technology

[0004] With the demand of the oil pipeline transportation market at this stage, the manufacture of SAWH steel pipes with large wall thickness is in sight. Due to the continuous increase in wall thickness of steel pipes, the existing ultrasonic automatic flaw detection equipment is not capable of completely covering such large wall thickness steel pipes. In order to improve the flaw detection capability, new inspection methods must be added for the transformation of large-wall-thickness steel pipe inspection and meet the final full coverage of the welding area.

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