How To Use A Portable Hardness Tester

A portable hardness tester has its own charm. With its sleek body, it manages to lure customers into buying the product. And what can be better than having a device that can be held in your hand; you just press a button and voila, your work is done.

However, you have to be extra careful with portable hardness testers. If not used correctly, they may fail to give accurate results. This is because hardness is not a direct measurement, but a comparative one. It actually signifies to what degree a sample is resistant to permanent notches and grooves.

The Common Mistakes

One of the most common mistakes that users commit is that they assume hardness to be a complete physical trait of a metal, similar to weight or width. Remember, a piece of brass that gives a specific hardness value may not have the same mechanical characteristics as that of a piece of steel with the same hardness value.

Another mistake is to assume that hardness scales can be converted in the same fashion as converting centimeters to inches. There are many factors that lead to product failure, such as use of inappropriate parts, wrong procedure, incorrect conversion charts, and ignorance regarding the usage of hardness testers.

Things to Remember

Take care of the following things while testing the hardness:

Test the hardness of the exact spot. It is silly to test the hardness of the center of saw, when you want to know the hardness the edge of the blade.

The surface to be tested should be polished, in order to detect indentations clearly.

Hold the test surface either parallel or at 90 degrees to the indenter.

Use the maximum load for testing. Heavy loads create big grooves that give a more precise result.

The closeness of the test should not be less three indenter diameters as compared to the previous test. When you are closer to the edge, you are actually measuring the hardness of the air, not metal.

The tested sample should be at least 10 times thicker as compared to the depth of incision. If the surface is thinner, then you are measuring the anvil, not the surface.

Hence, it is vital to know how a portable hardness tester works. If you are not well versed with the technique of measuring hardness, it is better to take professional help. Happy testing!