The test method standards state procedures for conducting a daily verification of the Rockwell hardness machine. The intent of the daily verification is for the user to monitor the reproducibility of the hardness machine between indirect verifications. At a minimum, the daily verification should be performed each day that hardness tests are to be made for each Rockwell scale that will be used. It is recommended that the daily verification procedures be performed whenever the indenter, anvil, or test force is changed to ensure that these changes to the machine have not added error to the measurement due to occurrences such as erroneous adjustments, misalignment, or poor condition or cleanliness of the machine components.
Good Practice Recommendations
• Before performing the daily verification tests, ensure that the testing machine is working freely and that the indenter and anvil are seated adequately. The indenter to be used for the daily verification must be the indenter that will be used for testing.
• Whenever a Rockwell hardness machine fails a daily verification, the hardness tests made since the last valid daily verification may be suspect.
• It is highly recommended that the results obtained from the daily verification testing be recorded using accepted statistical process control techniques, such as control charts. This type of monitoring can alert the user to impending problems before the measuring capability of the hardness machine becomes unacceptable.