Poldi hammer hardness tester
The Poldi hammer hardness tester is a portable impact test method that uses a hammer blow to create indentations simultaneously in a reference specimen and the test piece. The hardness value is determined by comparing the indentation diameters.
Physicochemical Mechanism of Action
The Poldi hammer hardness tester uses the different hardness of metals to measure their strength. A heavy hammer blow creates identical impressions in the sample and the test piece. Hardness is determined by the diameter of these impressions: the smaller the diameter, the harder the material.
Metallurgical Relevance & Welding Risks
Hammer hardness testing is especially important for quality assurance of weld specimens. Incorrect hardness values can lead to cracks or deformation, since the material is not strong enough. Too high a hardness maximum can also lead to fracture points and reduced component life.
Workshop Practice & Instructions
1. Preparation: Make sure the specimens are clean and free of dirt particles, as these can affect the impression.
2. Striking: Give the hammer a firm, uniform blow to ensure even penetration into the sample and test piece.
3. Measuring the impression: Measure the diameter of the impressions with a precision measuring device. Compare this value with the reference value to determine the hardness of the test piece.
4. Evaluation: If the diameter of the impression in the test piece is smaller than in the reference sample, the material is harder. Conversely, a larger diameter means lower hardness.