Four quality inspection aspects of pipe fitting elbow

　　The pipe fitting elbow must be inspected at the welded joint, which is also an important measure to ensure the welding quality. When the pipe fitting elbow is finished, the weld is tested according to the technical requirements of the product. If the defect is not in conformity with the technical requirements, it should be repaired in time (if the serious unqualified can not be repaired directly). The common inspection of pipe fitting elbow quality includes three aspects: appearance inspection, NDT and mechanical performance test. These three are complementary to each other, among which NDT is the main one.

　　1, appearance check: generally observe with the naked eye, sometimes observe with 5-20 times magnifying glass. Surface defects can be found through weld inspection.

　　2. NDT: detect defects such as slag, blowholes and cracks hidden inside the weld. At present, the most commonly used are X ray inspection, ultrasonic testing and magnetic flaw detection. X ray inspection is the use of X ray for weld photography, according to the film image to determine whether there are defects, defects and types.

　　3, hydraulic test and pressure test: for pressurized containers requiring sealing, pressure tests and air pressure tests should be carried out to check the sealing and pressure capacity of the weld.

　　4. Mechanical performance test of pipe fitting elbow: nondestructive flaw detection can detect inherent defects of weld, but it can not explain the mechanical properties of metal in weld heat affected zone.