Comparative hardness testing
Comparative hardness testing is a quick way to check the heat treatment condition of parts by hand filing or with portable testers. It doesn't give exact numbers, just a qualitative check.
Physico-Chemical Mechanism of Action
The comparative hardness test is based on the subjective assessment of the behavior of metal samples under the influence of a solid, heavy object (e.g., a steel plate). Hardness is judged by the depth and width of the indentation or the difficulty of hand filing.
Metallurgical Relevance & Welding Risks
This method is useful for a quick check whether a component has the desired hardness profile. However, it cannot provide precise numerical values and is therefore less accurate than quantitative methods like the Brinell or Rockwell hardness scales. Misinterpretation can lead to inaccurate conclusions, posing risks to the functionality and safety of the component.
Workshop Practice & Instructions
Use a solid object like a steel plate or a special testing machine. Press the object onto the metal sample and judge the depth and width of the indentation or the difficulty of hand filing. Compare the result with a standard material or a known hardness level. Make sure the test is always done under the same conditions to get consistent results.