Assessment method for heat exchange tube wall sinking degree based on eddy current testing

Abstract

The invention relates to an assessment method for the heat exchange tube wall sinking degree based on eddy current testing. The assessment method comprises the following steps: (1) manufacturing a sampling tube which has the same material and size of a heat exchange tube to be detected, and pressing a plurality of sink marks on the outer surface of the heat exchange tube through a steel bar perpendicular to the axis of the heat exchange tube; (b) measuring the length L of each sink mark, the outer radius R of the heat exchange tube to be detected and the radius r of the steel bar, and calculating the tube wall sinking area S of each sink mark; (c) performing eddy current testing on the sampling tube with the pressed sink marks to obtain an amplitude value V of each sink mark, introducing the areas S and the amplitude values V into a formula (2) to obtain a plurality of groups of A values and B values, and averaging the A values and the B values to obtain A1 and B1; (d) performing eddy current testing on the heat exchange tube to be detected to obtain an amplitude value V of tube wall sinking of the heat exchange tube, and introducing the amplitude value V, the A1 and the B1 into the formula (2) to calculate a sinking area of the tube wall. Through the adoption of the assessment method, the sinking degree of the tube wall can be known visually and clearly, so that basis is provided for the treatment decision of the heat exchange tube to be detected.

Description

technical field [0001] The invention belongs to the field of power plant equipment detection, and relates to a detection of heat exchange tube walls, in particular to a method for evaluating the depression degree of heat exchange tube walls based on eddy current detection. Background technique [0002] Heat exchangers using heat exchange tubes for heat exchange are very common, and power generation sites such as nuclear power plants are no exception. During operation, the heat exchange tube of the heat exchanger is the most vulnerable part, and the depression of the tube wall during service is one of the main ways of damage to the heat exchange tube of various heat exchangers, especially the power plant condenser. [0003] The eddy current testing method is widely used in the in-service inspection of heat exchange tubes because of its high sensitivity and fast detection speed. However, there is still no accurate and effective quantitative determination method for the degre...

AI Technical Summary

Problems solved by technology

However, there is still no accurate and effective quantitative determination method for the degree of pipe wall sag. As a result, the equipment owner cannot know the degree of sag of the corresponding sag pipe based on the sag signal in the eddy current test, and thus cannot give a clear treatment opinion.