Hydrogen flake formation
Hydrogen flakes form when hydrogen recombines in forged or rolled parts under thermal stress, causing internal hairline cracks.
Physicochemical mechanism of action
Hydrogen flaking occurs when free hydrogen in metals recombines at high temperatures and forms flakes. These flakes can move under thermal stresses and cause cracks.
Metallurgical relevance & risks in welding
Hydrogen flaking leads to internal cracks that occur particularly in the center of forged or rolled components. These cracks can lead to hot cracks and deformation, which impairs the service life and load-bearing capacity of the material.
Workshop practice & instructions
To avoid hydrogen flaking, the melting process should be well controlled. The temperature should not be too high to release unwanted hydrogen. After forging or rolling, sufficient cooling is necessary to prevent flake formation. For special materials, a post-melting treatment such as austenitizing may be recommended.