Hardness Testing on Welds
Hardness testing on weld seams measures local hardness values in the heat-affected zone, the weld metal, and the base material. The goal is to limit unacceptable hardening.
Physical-Chemical Mechanism of Action
Hardness testing measures the strength of the material structure at different points of a weld seam. This is done by measuring the stress resistance of a material under a defined pressure.
Metallurgical Relevance & Risks in Welding
A weld seam that is too hard can lead to cracks and failure because it lacks enough flexibility. Excessive hardening can also impair the toughness of the material and reduce the lifespan of components.
Workshop Practice & Instructions
For a correct hardness test, it is important to measure at the right points: in the heat-affected zone (HAZ), the weld metal, and the base material. The precise hardness measurement should be done with a hardness clamp or a Brinell clamp. Permissible hardness limits vary by material and application, but it is important that the hardness of the weld metal is not higher than that of the base material.