Weld Shrinkage
Weld seam shrinkage is a shortening and distortion of the part due to thermal contraction as the weld metal cools. It requires compensation measures.
Physical-Chemical Mechanism of Action
Weld shrinkage occurs because the weld metal transitions from its liquid phase to a solid phase during solidification and cooling. This process leads to thermal contraction of the material as it compresses during solidification. The weld thus shrinks, causing shortening and distortion of the component.
Metallurgical Relevance & Risks in Welding
Weld shrinkage can lead to stresses in the component, which can cause cracks or notches. It also increases the risk of hot cracking and changes the dimensional accuracy of the part. In complex structures, it can lead to functional failures or safety issues.
Workshop Practice & Action Guidelines
To minimize weld shrinkage, the following measures should be taken:
• Use appropriate welding process and consumables that exhibit low contraction.
• Control cooling steps: cool the part slowly and more uniformly to avoid stresses.
• Use compensatory measures such as weld gap adjustment or special cooling systems.