The thickness of non-magnetic coating on magnetic metal (iron) substrate can be quickly and non destructively measured by magnetic thickness gauge after thermal spraying to meet the different requirements of customers.

Thickness gauge is used to measure the thickness of materials and objects. In industrial production, it is often used for continuous or sampling measurement of product thickness (such as steel plate, steel strip, film, paper, foil and other materials).

This kind of instrument has many advantages α Radiation β Radiation γ Radioactive thickness gauge with ray penetration characteristics; Ultrasonic thickness gauge using ultrasonic frequency variation; Eddy current thickness gauge based on eddy current principle; There are also thickness measuring instruments based on the principle of mechanical contact measurement.

The thickness gauge can be used to measure the thickness of rolled plate and strip on line and output in the form of electrical signal. The signal is transmitted to the display and automatic gauge control system to realize automatic gauge control (AGC) of strip thickness. At present, the common thickness measuring instruments are γ Radiation β X-ray, X-ray and isotope ray are placed at the exit or entrance side of the strip mill. When designing and installing the thickness gauge, it is necessary to work as close as possible to the work rolls under the possible conditions, so as to reduce the lag adjustment time of the plate thickness.

The testing methods of the thickness gauge mainly include: magnetic thickness measuring method, radial thickness measuring method, electrolytic thickness measuring method, eddy current thickness measuring method and ultrasonic thickness measuring method.

Precautions for measurement:

1. When testing, it should be noted that the metal magnetism and surface roughness of the standard sheet group should be similar to the test piece.

2. During measurement, the side head shall be vertical to the surface of the sample.

3. When measuring, pay attention to the critical thickness of the base metal. If it is greater than this thickness, the measurement will not be affected by the thickness of the base metal.

4. Pay attention to the influence of the curvature of the specimen on the measurement. Therefore, it is not reliable to measure on the curved specimen surface.

5. Before measurement, pay attention to whether other electrical equipment around will produce magnetic field, if it will interfere with magnetic thickness measurement.

⒍ when measuring, pay attention not to measure at the inner corner and near the edge of the test piece, because the sudden change of the surface shape of the test piece of the general thickness gauge is very sensitive.

⒎ keep the pressure constant during the measurement, otherwise the reading will be affected.

8. During the test, pay attention to the direct contact between the instrument probe and the tested part, so the ultrasonic thickness gauge shall remove the attached substances at the opposite end.