Root face
Root face width is the uncut edge height at the root of the joint that prevents the weld pool from breaking through.
Physicochemical Mechanism of Action
The land width influences the permeability of the weld pool. Too small a land width can lead to breakthrough of the weld pool, while a sufficiently large land width stabilizes the weld pool.
Metallurgical Relevance & Welding Risks
Too thin a joint root with a small land width can lead to breakthrough of the weld pool, which causes an incomplete weld and possible cracks or distortion in the material. A sufficiently thick joint root keeps the weld pool stable and ensures a clean weld.
Workshop Practice & Instructions
For most steel grades, the land width should be at least 1.5 mm. For especially fine or tricky tasks, the land width can be increased to 2 mm. Make sure the joint root is clean and smooth to ensure optimal permeability of the weld pool.