Residual magnetism flaw detection method and device for piston rings based on series-connection closed type magnetization

Abstract

The invention relates to a residual magnetism flaw detection method and a residual magnetism flaw detection device for piston rings based on series-connection closed type magnetization. The N pole and the S pole of single permanent magnet 2 and a piston ring 1 form an annular magnetic loop, the penetrating-through magnetization in a circumferential direction is realized by the maximum magnetic energy density, a workpiece is scanned by multiple space sensitivity scale magnetic-sensing detection units 4' in a circumferential direction after the magnet is separated, a leakage magnetic field generated by a flaw is picked up and is converted into an electrical signal, and whether a flaw exists in the piston ring or not is judged through signal mutation. According to the residual magnetism flaw detection method, different opening gaps and a trans-scale flaw in irregular cross section of the piston ring 1 can be detected through the array type magnetic-sensing detection units 4' surrounding the piston ring 1, and the flaw detection rate is high; and besides, the problems of magnetic noise and the blind flaw detection end part in magnetic flux leakage detection of the piston ring 1 are solved and the automatic flaw detection of the piston ring 1 can be realized.

Description

technical field [0001] The invention belongs to the technical field of non-destructive detection of magnetic flux leakage, and in particular relates to a piston ring residual magnetic flaw detection method and device based on series closed magnetization. Background technique [0002] Piston rings are metal rings used to embed in piston grooves. They are widely used in various power machinery, such as gasoline engines, compressors, hydraulic machines, trains, ships, yachts and other mechanisms. The quality of their products is very important for the normal operation of these power machinery. very important. It has various specifications, small thickness and width, and different defect scales. There are extremely small point defects and linear defects distributed along arcs. The defects are often distributed on edges or end faces, and their positions are disordered. It will be difficult to detect defects efficiently by adopting appropriate magnetization and detection methods....

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Problems solved by technology

This magnetization method is not stable, and the close proximity of the magnetic poles of the yoke or the contact with the component under test results in excessive magnetic attraction, making it difficult for the detection probe to move relative to the structure under test during the detection process. It is not easy to separate from the object to be tested, and it is also difficult to realize the one-time overall magnetization of the special structure of the entire piston ring

[0006] Another method is Yang Yun's "Local Flux Leakage Detection Method and Device for Bearing Rings" (Nondestructive Testing Branch of China Mechanical Engineering Society, 2013), which uses permanent magnet local magnetization to realize the detection of bearing rings, but still Magnetization and detection are carried out at the same time, and the external connection used for magnetization is relatively cumbersome

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