Magnetic Inspection of Thin-walled Welded Pipe


The magnetic defect detection of thin-walled welded pipe can only find defects on the surface and near surface of welded pipe, and can only quantitatively analyze the defects. The nature and depth of defects can only be estimated by experience. Magnetic testing is to detect defects by using magnetic flux leakage of ferromagnetic welded pipe with high magnetic flux. According to the measurement methods of magnetic flux leakage, it can be divided into magnetic powder method, magnetic induction method and magnetic recording method, the most widely used of which is magnetic powder method.


Permeation test of thin-walled welded pipe
Thin-walled welded pipe penetration inspection uses physical properties such as the permeability of some liquids to detect and display defects, including coloring and fluorescence detection, and can be used to detect defects on the surface of ferromagnetic and non-ferromagnetic materials.


Radiographic Inspection of Thin-walled Welded Pipe
Thin-walled ray detection is a flaw detection method, which uses the attenuation characteristics of materials and materials that can penetrate radiation to detect defects. According to the different ray used in flaw detection, it can be divided into three kinds: X-ray inspection, gamma-ray inspection and high-energy radiography.  Due to the different methods of displaying defects, each radiographic examination can be divided into ionization, screen observation, photography and industrial television. X-ray inspection is mainly used to inspect cracks, incomplete penetration, blowhole, slag inclusions in weld seam of welded pipe.


Ultrasound Flaw Detection of Thin-walled Tubes
Ultrasound welding of thin-walled tubes can be used to inspect internal defects, which are caused by the reflection at the interface of different media during the propagation of metals and other homogeneous media. Ultrasound can inspect any welding material, any part of the defect, and can detect the location of the defect more sensitively, but it is difficult to determine the nature, shape and size of the defect. Therefore, the ultrasonic testing of welded pipe is usually combined with radiographic examination.

The thick wall elbow connecting pipe fitting includes an arc elbow, which is characterized in that there is a straight through connection on the curved elbow. The thick wall elbow is made of cast iron, stainless steel, alloy steel, calcinable cast iron, carbon steel, non-ferrous metal and plastic. According to the different production process, it can be divided into: welding elbow, punching elbow, casting elbow, etc. The connection mode of thick wall elbow and pipeline is: direct welding (commonly used) flange joint, threaded joint and socket joint.


The structure of thick wall elbow is reasonable, the force of pipeline system is uniform, the pipeline system is simplified, the operation is convenient, the investment is saved, the pipeline resistance is reduced, the pipeline layout is optimized, the operation cost can be reduced, the air flow distribution can be balanced, and the pipeline can be reduced. Vibration and ensure safe operation of equipment and piping. According to the production process, it can be divided into: welding elbow, punching elbow, casting elbow, etc.