Hardness Testing Connection

Foremost to any Rockwell test process is identification of the proper hardness scale to be used on the component to be tested.

ASTM provides specifications for appropriate indent placement on Rockwell and Brinell hardness test blocks. The purpose of these distances is to ensure that any new indentation is not influenced by work hardening of the materials’ edge or material around a previous indentation, sometimes referred to as the “affected zone”. So what's the easiest way to accurately follow these specifications without impeding on your efficiency? Etching.

Often, individuals whom are intending to carry out micro hardness testing ask about the differences between a Knoop test and a Vickers test and why they should choose one form over the other. Great Question! And the best answer is that choosing the right form of hardness test is paramount in obtaining quality testing data.

Tester verification is a commonly asked question regarding adherence to the latest ASTM E18 testing standard.  Many individuals are curious about when it is appropriate and or required to have a verification performed.  Other common questions circling this topic include the differences between indirect verification and direct verification.

Material thickness is of primary importance when choosing a Rockwell hardness scale. Too great a test load can cause material flow to occur throughout the full material thickness and to therefore react against the tester anvil. This reaction results in erroneous readings and significant misinterpretation of the actual material hardness.

Indent spacing is a very common concern during specimen testing or coupon block verification. The purpose for these distances is to ensure that any new indentation is not influenced by work hardening of the materials’ edge or material around a previous indentation.

Are you interested in learning about other types of materials testing? Do you want to stay up-to-date with what’s happening in the materials testing industry?

If you are performing a hardness tests on a cylindrical, convex, or concave surface, your actual results may be inaccurate due to the curvature of the material. In most cases, these inaccurate results should be accounted and adjusted for when reporting actual material hardness.

It is the day and age of being efficient. We are seeing an increase in energy efficiency improvements on our houses, new and improved gas-efficient automobiles, and an increased demand for efficiency in the workplace. So why not increase the efficiency in your Knoop and Vickers Testing?

The majority of our customers are performing Rockwell tests on their materials and we often find ourselves stressing to them the importance of perpendicularity of the specimen to the indenter. Perpendicularity is one of the two fundamental requirements in Rockwell testing, with the other being that the test piece does not move or slip during the test.