How to test the corrosion performance of the flange?

by | Jun 17, 2022 | Industry Knowledge

Flange in the use of industrial structural parts, mainly to improve the role of connection, And keep the pipeline seal without leakage, however, many flanges in use for a period of time will appear their own corrosion aging, thus losing the sealing effect, so it is necessary to do regular corrosion tests on the flange. Here and share the next measurement flange corrosion process.

First of all, must be sure that the flange to its regular maintenance and testing, corrosion occurs, usually for the flange wall thinning, local pits and pitting. For stainless steel flange internal corrosion reasons and ways need to be carried out in accordance with a certain way and principle, can now be used more widely at home and abroad flange corrosion detection methods are magnetic flux leakage method and ultrasonic detection method.

The ultrasonic testing method is to use the pulse reflection principle of ultrasonic to measure the thickness of the wall after corrosion. The basic principle of the magnetic flux leakage method is based on the high permeability of ferromagnetic materials. The magnetic permeability of the flange corrosion defects is far less than the flange permeability, the flange is magnetized under the action of the external magnetic field, when there is no defect in the flange, the vast majority of magnetic lines through the steel pipe, at this time the magnetic lines uniform distribution; When the flange internal defects, the magnetic field line bending, and a part of the magnetic line leakage out of the steel pipe surface. The existence of defects can be determined by detecting the leakage flux from the magnetized flange surface.

In addition to the detection of the internal surface area of the flange wall, the probe will be perpendicular to the flange inner wall of the ultrasonic pulse. The ultrasonic probe then receives a reflection pulse from the external surface area of the tube. The distance between the pulse and the internal surface area reflects the thickness of the wall. Elbow in the actual detection needs to be carried out in accordance with the actual situation and instructions, according to the ultrasonic testing method to test a good way.

The ultrasonic inspection method is also suitable for measuring thickness and performance of metal of other metal structures.

In order to ensure that the installation of the flange does not leak oil, installation pay attention to what issues?

1, flange should have sufficient strength, fastening shall not deformation. Flange sealing surface should be flat and clean, install to clean up oil and rust.

2, gasket should have good oil resistance and anti-aging performance, and better elasticity and mechanical strength. Installation should be based on the shape of the joint selection of different sections and sizes of gaskets, and placed correctly.

3, flange fastening force should be uniform, rubber pad compression should be controlled in 1 / 3 left. 

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