Sagging
Sagging is the sinking of molten weld metal under gravity in position welding, leading to unacceptable cross-section distortion. Precise parameter control is required for overhead welding.
Physicochemical Mechanism of Action
Sagging occurs when the molten weld metal sags under the force of gravity in out-of-position welds. This leads to uneven stresses and cross-sectional deformations that impair the mechanical strength of the weld.
Metallurgical Relevance & Risks in Welding
Sagging can result in a narrowed weld bead, which compresses the microstructure and reduces strength. This increases susceptibility to cracks and hot cracking. Additionally, it can cause uneven stresses in the material, leading to corrosion or other mechanical issues.
Workshop Practice & Action Guidelines
To avoid sagging, parameters must be precisely controlled during overhead welding. This includes correct selection of filler metal, proper temperature control, and careful positioning of tools. A typical goal is to keep the weld cross-section as uniform as possible, which can be achieved by using backing tools and controlled movement of the welding torch.