Transition Cycle Number
The endurance limit cycle number is the point on the Wöhler curve where short-term strength transitions into long-term strength. It marks the end of the pure finite life region.
Physicochemical mechanism of action
The endurance limit cycle number (ELCN) is the intersection between the short-term and long-term fatigue strength in the logarithmic Wöhler curve. It marks the end of the pure finite life region, where material stress acts over the long term.
Metallurgical relevance & welding risks
Under overcritical loading, the material can fail suddenly before reaching the endurance limit cycle number. This leads to cracks and deformation, especially at high temperatures and rapid cooling. A too low ELCN value increases the risk of hot cracking and reduces the component's service life.
Workshop practice & instructions
To maximize the endurance limit cycle number, it is important to ensure optimal cooling steps. This includes avoiding rapid cooling and adhering to correct welding parameters. For high-carbon steels (e.g., HSS), the ELCN is particularly important because it offers higher resistance to hot cracking. The exact ELCN value should be determined depending on material and application.