Metal plate defect online detection method and device

Abstract

The invention discloses a metal plate defect online detection method and metal plate defect online detection device. Based on the fact that the heat conductivity of a homogeneous metal plate and the heat conductivity of internal holes, air bubbles or other impurities are different and the fact that the metal plate has a higher heat conductivity and higher heat conducting speed, when the metal plate is instantly sprayed with a cooling or heating medium at a certain temperature, the part, without defects, of the metal plate can restore the temperature quickly and has a uniform infrared image and no abnormal spots, while the part with defects of internal holes, air bubbles or impurities have abnormal spots due to the deference between the heat conductivity of the holes, air bubbles or impurities and the heat conductivity of the metal plate. The metal plate defect online detection device consisting of thermal infrared imagers, a cooling or heating medium spraying or blowing device and a digital program control device synchronously performs control, captures an infrared image and compares and analyzes the obtained infrared image at a fixed time according to preset process steps and canaccurately and conveniently detect the defects including through holes in the metal plate on line.

Description

technical field [0001] The invention relates to the technical field of metal plate quality detection, in particular to an infrared thermal imaging detection technology for detecting impurities such as holes or air bubbles in the metal plate. Background technique [0002] Metal sheets, especially thin sheets, such as steel sheets, aluminum sheets, and copper sheets, often have holes or impurities mixed in during the rolling process due to various reasons during the production process. Such products are unqualified products. In order to solve the problem of detecting holes, It is understood that Thermo Fisher Scientific Corporation of the United States produces a hole tester, but it can only detect through holes but not blind holes, let alone determine the position and size of holes. [0003] Chinese Patent CN1758967A (International Application No. PCT / FR2004 / 000679) discloses a component for detecting holes in a continuously advancing material web. The inventive part is of t...

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Problems solved by technology

The invention can be used to inspect the holes on the steel plate that advances continuously at high speed, and uses the point-to-point method of the light emitting subassembly and the light receiving subassembly to detect the holes on the steel plate. through-holes, but cannot detect non-penetrated holes, and cannot detect defects such as air bubbles and impurities contained in the steel plate, cannot accurately display the position of the defect, and cannot display the detected image

The device can directly display the specific location of the hole. However, since it uses ultraviolet light to detect the hole in the steel plate, it is not only inconvenient to detect, but it still cannot detect the unpenetrated hole on the steel plate, nor can it detect the air bubbles contained in the steel plate. And impurities and other defects, but also susceptible to interference from other light sources

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