Instrumented indentation testing
Instrumented hardness testing measures the hardness of a material continuously during indentation. It provides not only hardness but also elastic properties such as the elastic modulus.
Physicochemical Mechanism of Action
Instrumented Indentation Testing (IIT) continuously measures a material's hardness during indenter penetration. The indenter is pressed into the material, and the force needed for penetration is measured by a sensor. This force is then converted into a hardness value.
Metallurgical Relevance & Welding Risks
IIT is especially important for controlling the hardness of weld zones, particularly in high-hardness steels like martensitic or austenitic. A weld that's too hard can crack or fracture, while one that's too soft can deform and have lower strength. So IIT helps ensure the weld hardness stays within the specified range.
Workshop Practice & Action Steps
To perform a proper IIT, follow these steps:
1. Prepare the indenter: Make sure the indenter is clean and free of contaminants.
2. Select the material: Choose the right reference material that matches the workpiece.
3. Indent the material: Let the indenter penetrate continuously and record the force needed.
4. Data analysis: Use specialized software to analyze the data and calculate the hardness.
5. Verify results: Compare the measured hardness against the specified standards or specs for the workpiece.