Crack Tip Opening Displacement
Crack opening path is the distance between the crack start and the first full through-thickness tear. It measures the plastic deformation before crack penetration.
Physical-Chemical Mechanism of Action
The crack opening path describes how far a crack propagates before it fully penetrates. This process involves plastic deformation of the material around the crack.
Metallurgical Relevance & Risks in Welding
A too-large crack opening path can lead to increased crack resistance, which can be advantageous in tough materials. However, it can also lead to increased stress concentration and potential hot cracking if the weld is not cooled properly.
Workshop Practice & Instructions
When welding tough materials, it is important to control the crack opening path. This can be achieved by careful cooling of the weld. The critical temperature window (t8/5) should be maintained: t8/5 < 20 s for soft microstructures and t8/5 > 10 s for harder microstructures, to achieve optimal crack resistance.