Sometimes when you are using metal such as steel for projects, it is beneficial to understand how hard the metal is. Knowing the hardness of steel lets you know how well it will hold up under certain types of force. When choosing a steel hardness tester, it helps to understand some of the different methods for testing the hardness of metals. There are four main methods commonly used for such testing: sclerometer, scleroscope, indentation, and drill.
The sclerometer test was invented by Turner in 1896. It draws a diamond point backward and forward over the metalsurface. Whatever the weight is in grams that causes a scratch on the material becomes the hardness number.
The scleroscope test was invented by Shore and may also be known as a Leeb rebound hardness test. It allows a hammer with a hard point to fall on the metal surface being tested. The height of the rebound is measured as the hardness number. It may be particularly common to see this used as a steel hardness tester.
Indentation, also known as Brinell’s Test, is done by pressing a steel ball into the surface of the test metal. The area of the indentation is then calculated along with the known pressure and stress per unit of area. This creates the hardness number.
Drill, or Keep’s Test, uses a steel drill pressed to the surface of the test metal for so many revolutions. The hardness is determined by comparing to a diagram where soft material produces a horizontal line and material that is the same hardness as the drill produces a vertical one.
A steel hardness tester comes in many different forms. It is important to understand which method you will be using, as the numbers that are produced may be different for each method. You also need the right type of equipment to properly carry out each test. You should look up the guidelines for accurate set up and execution of each testing method.
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