Water wall tube inner wall corrosion defect ultrasonic detection simulation test block and detection method

Abstract

The invention belongs to the technical field of water-cooled wall tube detection, and discloses a water-cooled wall tube inner wall corrosion defect ultrasonic detection simulation test block and a detection method.The water-cooled wall tube inner wall corrosion defect ultrasonic detection simulation test block is used for making a DAC curve, and the simulation test block comprises a first blind hole module, a second blind hole module and a third blind hole module; making a DAC curve by using 80% of the reflected wave height of the blind hole of the first blind hole module, further adjusting each point of the DAC curve through the actual reflected wave height of the blind hole of the second blind hole module, verifying the reasonability of the curve through the blind hole of the third module, and ensuring that the blind hole equivalent of the third module is DAC + 6db; according to the method, the simulation test block is used for verification, the standard measurement value of the water wall tube inner wall corrosion defect is formulated according to the reflection signals of the blind holes in different positions in the simulation test block, and the detection precision and the working efficiency of ultrasonic detection of the water wall tube inner wall corrosion defect are improved.

Description

technical field [0001] The invention belongs to the technical field of detection of water-cooled wall tubes, and more particularly relates to a simulated test block and a detection method for ultrasonic detection of corrosion defects on the inner wall of a water-cooled wall tube. Background technique [0002] The water wall is welded by small diameter tubes and fins. As an important part of the boiler to absorb heat, under the comprehensive influence of thermal convection, heat radiation, the decrease of deaerator efficiency, the increase of oxygen content in the water, and the increase of impurities in the water, the inner wall of the water wall is A chemical reaction occurs to form rust accumulation, which causes scaling on the inner wall of the water-cooling wall, resulting in corrosion under the scale, which frequently causes the boiler water-cooling wall to burst and leak, affecting the safe and stable operation of the boiler unit. [0003] At present, the non-destructi...

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Problems solved by technology

However, there is no simulated comparison test block for ultrasonic detection of corrosion pits on the inner wall of water-cooled wall tubes in China. The standard test block has a large calibration gap, especially in the relative lack of sensitivity in detecting corrosion on the inner wall of boiler water-cooled wall tubes, resulting in inaccurate test results and defects. Judgments and missed inspections, there are great quality and safety hazards

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