Ultrasonic thickness gauge measurement technology and the use of methods
1 Clean surface
Ultrasonic thickness gauge should be measured before the surface of the object all the dust, dirt and corrosion, eradication of paint and other coverings.
2 Improve the roughness requirements
Excessive roughness of the surface will cause measurement errors, and even the instrument does not read. Ultrasonic thickness gauge before measurement should try to make the measured material surface smooth, can use grinding, throwing, filing and other methods to make it smooth, can also use high viscosity coupling agent, choose coarse crystal probe SZ2.5P.
3 Rough machining surface
Rough machining surface (such as lathe or planer) caused by the regular fine grooves will also cause measurement errors, make up for the same method 2, in addition to adjusting the probe tandem spacer plate (through the centre of the probe bottom surface of the thin layer) and the measured material fine grooves between the angle, so that the spacer plate and the fine grooves perpendicular to each other or parallel to the readings taken in the * small value of the thickness as a measurement, you can achieve better results.
4 ultrasonic thickness gauge measuring cylindrical surface
Measurement of cylindrical materials, such as pipes, oil drums, etc., the choice of probe string tone spacer plate and the measured material axis between the angle is critical. Simply put, the probe will be coupled with the measured material, the probe crosstalk spacer and the measured material axis parallel or perpendicular, along the direction of the measured material axis perpendicular to the slow shake of the probe, the readings on the screen will change regularly, select the smallest value in the readings, as the exact thickness of the material. Select the probe crosstalk spacer plate and the measured material axis of the intersection of the angle direction of the standard depends on the curvature of the material, the diameter of the pipe, select the probe crosstalk spacer plate and the pipe axis perpendicular to the pipe, the diameter of the pipe is small, then select the pipe axis parallel and perpendicular to the two methods of measurement, to take the readings in the * small value as a measurement of the thickness.
5 Composite shape
When measuring the composite shape of the material (such as pipe elbow) can be used 7.4 introduced method, the difference is to carry out the second measurement, respectively, read the probe crosstalk sound insulation plate and axis perpendicular and parallel to the two values, and the smaller one as the thickness of the material at the measurement point.
6 Non-parallel surfaces
In order to obtain a satisfactory ultrasonic response, the other surface of the material to be measured must be parallel or coaxial with the measured surface, otherwise it will cause measurement errors or no readings at all.
7 Effect of material temperature
Material thickness and ultrasonic propagation speed are affected by the temperature, if the measurement accuracy requirements are high, the same material can be used in the same temperature conditions of the test piece were measured, the temperature of the material to calculate the measurement error to provide parameters to correct it, for steel, high temperature will cause a large error, can be compensated for the correction of this method.
