How to Test the Hardness of Steel

Rockwell Hardness testing can be used for determining the hardness of soft and harder metals including steel. The American Society for Testing and Materials (ASTM) has established a standard recognized worldwide to help manufacturers maintain the qualities they want in their products.  ASTM Standards E-18 and E-110 defines the test method and parameters for a valid test using portable hardness testers. Rockwell hardness testing is a way of measuring the hardness of steel. Hardness means resistance to penetration. This test gets its name from Stanley P. Rockwell who invented the test and the original hardness testing machines.

Using the Rockwell method to test steel hardness

The Rockwell hardness testing of steel parts is done by applying loads to parts via either a tungsten carbide ball or a  diamond indenter.  The surface of the steel part has to be ready before the testing can begin.  If it is not, the chances of inaccurate readings rise.

Next, a light load is applied to the indenter or penetrator (usually either 3 or 5 kgf) to zero out the portable Rockwell hardness tester. Next, a heavy load ( from 15 kgf to 150 kgf) is applied and held for a period of time.

The length the indenter traveled from the application of the light load to the release of the heavy load is documented and used to determine the hardness of the steel

Rockwell hardness is determined by measuring the distance traveled by an indenter when a heavy load is applied to a heat-treated part. The Rockwell method is the most common and accurate way to get a calculation on the hardness of steel

Take a look at the video below for further instructions on using an Ames portable Rockwell hardness tester.

Further reading

What metals can Rockwell hardness testers be used with?

How to Test the Hardness of Steel

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