Excessive root penetration sag

Physical-Chemical Mechanism of Action

During welding, a molten layer forms between the workpieces. If this layer becomes too thick or does not cool properly, it remains as sagging on the underside of the part.

Metallurgical Relevance & Risks in Welding

Macroscopic sagging can cause uneven stress distribution and lead to the development of cracks or hot cracks in the material. Additionally, it can impair the mechanical properties of the weld by altering the contact area ratio.

Workshop Practice & Action Instructions

To avoid macroscopic sagging, ensure proper molten pool coverage and even cooling of the weld. Use a suitable backing bar or chill bar to relieve the molten pool. In severe cases, an additional grinding pass may be required.