Instrumented indentation test
Instrumented indentation testing (IIT) electronically measures force and displacement during the loading cycle. It provides detailed information about the elastic-plastic properties.
Physicochemical Mechanism of Action
IIT uses an instrumented indenter tip that applies a constant force to the test material. During the indentation, the displacement of the material is continuously measured and recorded electronically. This allows precise analysis of the hardness profile and plastic deformation of the material.
Metallurgical Relevance & Risks in Welding
IIT is particularly useful for testing weld zones. It can determine whether the hardness distribution in the material is correct and whether there are cracks or uneven deformations. Incorrect values may indicate that the material was not properly welded or that it is excessively deformed or overstressed.
Workshop Practice & Operating Instructions
To perform IIT correctly, the following steps should be observed:
1. Material preparation: Make sure the test material is clean and free of contaminants.
2. Instrument calibration: Calibrate the IIT before each test to eliminate measurement errors.
3. Apply the force: Apply a constant force to the material, which is set depending on the material to be tested and the desired accuracy (usually between 500 N and 1000 N).
4. Measure displacement: During indentation, the displacement is continuously measured and recorded.
5. Data evaluation: Analyze the collected data to determine the elastic-plastic properties and to identify potential issues.