Qualitative detection method for cold roller surface micro linear defect

Abstract

The present invention discloses a qualitative detection method for the cold roller surface micro linear defect. According to the qualitative detection method, ultrasonic surface wave and magnetic particle inspection is adopted to detect the cold roller surface; the micro linear defect is positioned by using a metallurgical defect positioning scale; the defect part is subjected to coarse grinding, fine grinding and polishing with sand paper and is corroded, the morphologies of the linear defect and the microstructure surrounding the linear defect are copied by using acetate fiber paper, and the defect is marked so as to complete the preparation of the defect morphology copying sheet; the defect morphology copying sheet is subjected to vacuum carbon spraying, the microstructure morphology of the defect is observed under a microscope, the change of the microstructure close to the defect is observed, and the characteristics of the defect morphology and the surrounding microstructure morphology are recorded; and according to the micromorphology characteristic of the micro linear defect and the characteristic of the microstructure surrounding the defect, the character of the roller surface linear defect is qualitatively judged. With the detection of the present invention, the qualitative judgment can be performed on the cold roller surface micro linear defect, such that the cold roller subsequent grinding treatment is convenient, the cold roller service accident is avoided, and the cold rolling quality of the plate is ensured.

Description

technical field [0001] The invention relates to a qualitative detection method for small linear defects on the surface of cold rolls. Background technique [0002] After the forged steel cold roll is used, it is necessary to grind off the defects on the surface of the cold roll such as pits and roll marks during the maintenance process. And the formation of local surface microcracks; According to statistics, 80% of the stripped fatigue spalling of cold rolling rolls is caused by surface microcracks. Therefore, cold rolled rolls must not be used in a state with surface cracks. [0003] Once the small defects on the surface of the cold roll are not eliminated, it is very easy to cause the degradation of the quality of the plate, the peeling of the cold roll, the breakage of the roll and other major accidents. In order to avoid this situation, the existing detection technology is that the roll grinder is equipped with an automatic eddy current flaw detection device to detect...

AI Technical Summary

Problems solved by technology

Therefore, cold rolls must not be used in the state of surface cracks

[0003] Once the small defects on the surface of the cold roll are not eliminated, it is very easy to cause the degradation of the quality of the plate, the peeling of the cold roll, the breakage of the roll and other major accidents.

However, for some cold rolls after grinding, some small linear point defects will appear on the roll surface. These defects are difficult to find with the naked eye, and it is usually difficult to find them with automatic eddy current flaw detection devices. They can be observed with ultrasonic surface wave detection and magnetic particle flaw detection. , but the nature of the linear defect cannot be determined, causing certain difficulties to the subsequent grinding process

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