Measuring method of blind flange corrosion

　　First of all, it must be affirmed that the blind flange should be maintained and inspected regularly. After corrosion, it usually shows that the ASME B16.5 A105 Stainless Steel Blind Flange pipe wall becomes thinner and local pits and pits appear. The causes and modes of internal corrosion of stainless steel blind flange need to be carried out in accordance with certain ways and principles. Flux leakage method and ultrasonic detection method are widely used in blind flange corrosion detection at home and abroad.

　　The ultrasonic method is to measure the thickness of corroded pipe wall by using the principle of pulse reflection of ultrasonic wave. The basic principle of magnetic flux leakage method is based on the high permeability of ferromagnetic materials. The permeability of blind flange corrosion defect is far less than that of blind flange. The blind flange is magnetized under the action of external magnetic field. When there is no blind flange defect, most of the magnetic lines pass through the steel pipe, and then the magnetic lines are evenly distributed. When there are defects in the blind flange, the magnetic lines occur. By bending and detecting the leakage flux from the magnetized blind flange surface, we can judge whether the defect exists or not.

　　In addition, the probe emits ultrasonic pulse vertically to the inner wall of the blind flange. The probe first receives the reflected pulse from the inner surface of the tube wall, and then the ultrasonic probe receives the reflected pulse from the outer surface of the tube wall. The distance between the reflected pulse and the inner surface reflects the thickness of the tube wall.

　　The ultrasonic testing method is also suitable for thickness measurement and metal properties measurement of other metal structures.