In actual production, a layer of non-magnetic coating is often adhered to the inner and outer surfaces of the steel pipe, which may be plastic, paint, copper or chromium layer, or enamel or galvanized. On the one hand, it plays a protective role, and on the other hand, it also plays a decorative role.
The thickness measurement of the coating is particularly important. Generally, the coating of steel pipes is detected by using a magnetic Thickness Gauge. The principle of the magnetic Thickness Gauge is developed through the air gap principle of the long-term magnetic two-level quality inspection. At this stage, the research and development technology of magnetic Thickness Gauges is very mature, and the digital display function, automatic judgment of the substrate function, and accuracy have been accepted by most industry users.
Taking the magnetic Thickness Gauge produced by Defelsko in the United States as an example, its measurement options include general-purpose probes with a range of 0-1500 μm, and micro-probes specially used to measure aluminum-based oxide films and 0-625 μm, and even 0-6mm. , 0-13mm ultra-thick probe, and the probe of the Thickness Gauge can be replaced, to a certain extent, it takes into account the on-site testing environment and the special requirements of customers, and also saves costs, and does not need to purchase multiple hosts repeatedly.
The accuracy of the Thickness Gauge is undoubtedly an important indicator to measure the quality of the Thickness Gauge. The American Defelsko Thickness Gauge can reach (1μm+1%) according to the different test probes. And it has the storage function of measurement data, which can automatically display the average value, standard deviation, maximum and minimum values, etc. Very convenient.
For the thickness measurement of the steel pipe coating, the author recommends using a Thickness Gauge with a wire probe. This kind of Thickness Gauge with a wire probe is more convenient for measuring the thickness of the inner wall coating. , In the actual coating thickness measurement, often the inner wall of the steel pipe cannot be measured with an integrated Thickness Gauge. Another incidental advantage is that the probe of the coating Thickness Gauge with wire can be replaced freely (take the Defelsko Thickness Gauge as an example), so that the cost will be saved, and it can be used for the new environment of coating thickness measurement in the future. bring a possibility.
American Defelsko Split Magnetic Thickness Gauge
