Root Gap Width
The root gap is the distance between the edges of the parts to be joined. It determines whether the welding process covers the entire root area.
Physico-chemical mechanism of action
The root gap influences the diffusion rate of metal ions and gases. A gap too large can lead to incomplete fusion, while a gap too small leads to overlap or a too-narrow gap.
Metallurgical relevance & welding risks
A too-large root gap (e.g., > 2 mm) can cause the root area not to be fully covered, leading to incomplete fusion and possible cracks. A too-small gap (e.g., < 0.5 mm) can cause overlap and a too-narrow gap, which can lead to zinc spots or stress areas in the weld.
Workshop practice & instructions
For most steel types, the root gap should be between 0.5 mm and 2 mm. For high-performance welding processes like TIG or MIG, a precisely maintained gap is crucial. Use a gap gauge or a joint alignment tool to ensure the correct gap.