What aspects to be aware of when using a hardness tester

A hardness tester is a hardness test instrument
.

Metal hardness measurements indicate a material's ability to
resist hard objects pressing into its surface.

It is one
of the important performance indicators of metal materials.

The higher the
general hardness.

Use of precautions 1, the hardness tester itself will produce two kinds of errors: one is the deformation of its parts, the error caused by movement; The second is the error
caused by the hardness parameter exceeding the specified standard.

For errors, the hardness tester needs to be calibrated
with a standard block before measuring.

For the Rockwell hardness tester correction results, the difference is within
±1.

A stable value with a difference of ±2 can give a corrected value
.

When the difference is outside the range of ±2, the hardness tester must be corrected and repaired or measured by another hardness test method
.

2.
When replacing the indenter or anvil seat, pay attention to the contact part to be wiped clean
.

After changing, the hardness of the steel sample should be tested several times until the hardness value is the same for two consecutive times
.

The purpose is to make the indenter or anvil and the testing machine contact part of the compression, good contact, so as not to affect the accuracy
of the test results.

3.
After the hardness tester is adjusted, when the hardness is measured, the test point is not used
.

For fear that the specimen will not come into good contact with the anvil, the measured value is inaccurate
.

After the point test is completed, the hardness tester is in the normal operation mechanism state and then the specimen is formally tested to record the measured hardness value
.

4.
In the case of the test piece allowing, it is generally selected to test at least three hardness values in different parts, take the average value, and take the average value as the hardness value
of the test piece.

5.
The specimen with complex shape should be used with the corresponding shape of the pad, and it can be tested
after fixing.

Round specimens are generally tested in a V-shaped groove
.

6.
Check whether the loading handle is placed in the unloading position before loading, and the action should be light and stable when loading, and do not use too much
force.

After loading, the loading handle should be placed in the unloading position, so as to avoid the instrument being in a state of load for a long time, plastic deformation, and affecting the measurement
.