Incomplete root penetration
The weld doesn't fully penetrate the base metal, leaving a thin notch effect and low load capacity.
Physical-Chemical Mechanism of Action
During welding, a molten pool forms around the workpiece. If the weld metal does not fully penetrate, an unfused zone remains at the bottom of the weld. This prevents a homogeneous joint and creates a notching effect.
Metallurgical Relevance & Risks in Welding
Incomplete penetration can lead to cracks, hot cracks, or fracture under load. The load capacity of the joint is significantly reduced because the notch effect is not strong enough.
Workshop Practice & Actions
To avoid incomplete penetration, pay attention to the correct welding direction and sufficient molten volume. Use a suitable filler metal with the right composition. Make sure the workpiece is flat and has no unevenness. Check penetration regularly by ultrasound or X-ray inspection.