Fatigue Notch Sensitivity

Physicochemical Mechanism of Action

Fatigue notch effect describes how a material responds to repeated mechanical loads. At geometric cross-section changes or surface notches, the material can be distorted by a small angle with each oscillation. These microscopic distortions can add up over time and lead to micro-deformations, eventually causing fatigue failure of the material.

Metallurgical Relevance & Risks in Welding

During welding fabrication, the material can be affected by geometric cross-section changes or surface notches under cyclic loads. Excessive fatigue notch effect can cause the material to crack under normal loads. This increases the risk of cracking and reduces the service life of the component.

Workshop Practice & Action Guidelines

To minimize the fatigue notch effect, during welding fabrication:

• Choose as smooth a cross-section as possible.

• Reduce the notch width to a minimum.

• Use high frequency and low amplitude of vibrations.

• If necessary, the material can be processed before welding by hardening or forming to increase its fatigue notch effect.