Hardness Testing Aluminum Castings

Hardness is the measurement of the resistance of a metal to plastic deformation. The process for checking the hardness of a material may vary but it usually consists of the use of an indentation that is measured in a casting. Hardness is the property that shows a materials ability to resist permanent deformation when it is under load. The greater the hardness of a material the greater the material will resist deformation. At Ramsden Industries, we are able to perform two specific types of hardness testing: Brinell and Leeb Testing.  

Brinell Hardness Testing 

The Brinell hardness test is measured by forcing a hardened steel or carbide sphere into a casting under a specified load. The indentation that is created in the metal is measured for its diameter. A Brinell hardness reading is obtained by dividing the load used (in Kg) by the area of the indentation in the casting being tested (in square mm). When measuring an aluminum alloy a 500Kg load is used, along with a sphere of 10mm.  

Leeb Hardness Testing 

The Leeb hardness test uses an impact object of a certain weight, which is pounded at the surface of the casting being tested under a certain predetermined force. A calibrated hardness-testing instrument will determine both the impacting velocity and the rebounding velocity of the impacting object when they are both 1mm from the testing surface. The Leeb hardness value is expressed as a ratio of the rebounding velocity to the impacting velocity. The harder the material is the faster the velocity will be when the impact object is rebounding. The Leeb value that is obtained is used in comparison with industry standards to determine the hardness using a Rockwell, Brinell, and Vickers

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