This paragraph only introduces the detection method of Rockwell hardness tester, which is widely used in the testing industry. And I will analyzes the common influencing factors that are easily overlooked by the inspectors in the detection process and puts forward the solution.
The application of hardness tester in the electronics factory, mold engineering, food factory is very extensive, and when the hardness tester used to a certain extent, it need to be test or calibration equipment maintenance. So how can we avoid errors and the impact of its accuracy in the process.
1. The indenter or anvil contact parts should be kept clean while change it. Then you need to test several times with a certain hardness steel until the hardness of two times are the same. The purpose is to make the contact part of indenter or anvil and the test machine tightly so as not to affect the accuracy of the test results.
2. The hardness itself will produce two kinds of errors. One is the error caused by the movement and distortion of its parts; Second is the error due to hardness parameters beyond the provisions standard. For the second error, you need to use a standard block to calibrate the durometer before measuring. For Rockwell hardness calibration results, the difference is within ± 1. The difference between ± 2 within the stable value, you can give a correction value. When the difference is outside the range of ± 2, the hardness tester must be calibrated or tested by other hardness test.
3. To check whether the loading handle on the unloading position before loading, load action should be light and stable, and do not force too much. The loading handle should be placed in the unloading position after load, so that the instrument is not in a state of long-term load and occurs plastic deformation to affect the measurement accuracy.
4. Use the corresponding shape of the pad for the complex shape of sample, and fixed before the test. The test piece is generally placed in a V-groove.
5. After the instrument maintenance hardness adjustment and began to measure the hardness, the first test point is not used. The measured value is not accurate due to the poor contact with the anvil. After the first test, the hardness tester is in the normal operating mechanism state, the formal test of the sample can begin and you can record the measured hardness value.
6. In the case of allowing the test, at least three hardness values are selected generally for different parts, take the average value as the hardness of the specimen.
Hardness tester in the test beyond its specified test range, its hardness and accuracy is not accurate, then it should not be used. The standard block for the calibration the hardness can not be used on both sides, because the standard surface and the back of the hardness is not necessarily the same. The hardness after maintenance must be adjusted before use. And generally the standard block is effective within one year from the date of calibration.