Excessive Root Sag

Physicochemical Mechanism of Action

The molten pool hangs too much on the underside of the root when the heat input is too high and the surface tension is insufficient. This causes uneven stresses and geometric distortion.

Metallurgical Relevance & Welding Risks

Excessive root sag can lead to cracks, deformation, and a poor weld. The stress distribution is disturbed, which impairs the toughness of the joint.

Workshop Practice & Instructions

To avoid excessive root sag, ensure appropriate heat input and strengthen the surface tension. Keep the molten pool as tight as possible on the underside of the root. If necessary, use additional stress distribution methods to minimize geometric irregularities.