Charpy V-notch specimen
The Charpy V-notch specimen is a standard specimen with a V-shaped notch, used to determine the impact work of welds and base materials. It indicates the material's endurance under sudden stress spikes.
Physico-chemical mechanism of action
The Charpy V-notch specimen consists of a bar with a V-shaped notch, which is placed in a test fixture. In the impact bending test, the material is suddenly stressed and breaks at the notch. The energy released during fracture is measured as impact work.
Metallurgical relevance & risks when welding
The Charpy V-notch specimen provides information about the mechanical toughness and stress absorption of the material. A low value indicates lower endurance and higher susceptibility to cracking. In poor welds, the Charpy value can significantly drop, increasing the risk of hot cracks.
Workshop practice & action instructions
To perform the Charpy V-notch test, a bar with a V-shaped notch is placed in a test fixture. The impact is then executed and the released energy is measured. A typical value for high-quality steel grades is over 40 J/cm². For welds, the Charpy value should be at least 25 J/cm² to ensure sufficient toughness.