Method and apparatus for on-line detecting the depth from the Curie point temperature layer to the surface of a hot steel plate

Abstract

The invention concerns method to detect the depth of Curie point temperature layer of hot steel plate on-line to surface. Applying electromagnetic eddy current principle, simulates hot steel plate by stainless steel plate and general steel plate with thickness known and scales the function expression format of depth of Curie point temperature layer of hot steel plate to surface for practical measurement. The detection apparatus comprises two same eddy current sensors, one of them detects close up to surface of hot steel, another close to general steel plate of standard clad steel plate to detect; both of all are activated by a low frequency signal, and output the thickness deviation information phase-agile detected by differential amplify; uses the function expression to process the depth data by data processing unit with microcomputer as core. The apparatus is used to detect and adjust technological parameter real-time, simple to carry out, and is better to anti-noise.

Description

Technical field [0001] The invention relates to a device for measuring the thickness of a steel plate by electromagnetic means, in particular to an electromagnetic measuring device for online detection of the Curie point temperature layer distance from the surface of a hot-rolled steel plate. Background technique [0002] In the production process of the hot-rolled steel plate, in order to control the quality of the steel plate, it is necessary to prevent tiny cracks on the surface, so that the cracks will be lengthened or widened in the subsequent rolling process. For this reason, the conventional method is to measure the temperature of the hot steel plate, and based on this, adjust the process parameters such as the feeding speed of the steel plate or the pressure of the roll. However, it is difficult to accurately measure the temperature of the hot steel plate, especially in the production process of hot-rolled medium and thick steel plates at 600°C-1100°C, the temperatur...

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Problems solved by technology

Since the depth of the Curie point temperature layer from the surface of the hot-rolled steel plate changes dynamically, it is impossible to use this method to pre-measure the corresponding relationship between the coil impedance and the change of the Curie point temperature layer from the surface depth of the hot-rolled steel plate; in addition, the coil impedance measurement The results are also affected by various disturbance factors on site, even if the above corresponding relationship is obtained, the depth of the Curie point temperature layer from the surface of the hot-rolled steel plate cannot be correctly inferred in real time.

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