Hydrogen-Induced Cracking Index
The hydrogen-induced cracking index (HICI) measures the susceptibility of a weld to hydrogen cracking. It considers microstructure, stress, and hydrogen concentration. A high HICI indicates an increased risk zone.
Physical-Chemical Mechanism of Action
Hydrogen can diffuse into metals and accumulate there. Under certain conditions, such as high stress or specific microstructures, this hydrogen can lead to cracking. The WIRBI calculates the probability of such cracks through a combination of factors like hydrogen concentration and mechanical loading.
Metallurgical Relevance & Risks in Welding
A high WIRBI indicates an increased susceptibility to hydrogen-induced cracking. This can lead to critical failures, such as deterioration of mechanical properties or even crack formation in the weld. It is especially important for highly stressed components or in environments with high hydrogen content.
Workshop Practice & Action Instructions
To reduce the WIRBI and minimize the risk of hydrogen cracking, the following measures should be taken:
• Use welding consumables with low susceptibility to hydrogen.
• Ensure proper cooling of the weld to achieve a homogeneous microstructure.
• Avoid high stresses in the weld zone through careful planning and execution of the welding procedure.