Cut edge hardened zone
The heat-affected zone at the cut edge is formed by rapid cooling after the cutting process and has increased hardness, which promotes crack formation.
Physical-Chemical Mechanism of Action
After thermal cutting processes such as welding or milling, the metal edge cools down very quickly. This leads to rapid deformation of the crystal structure, which causes hardening of the edge zone.
Metallurgical Relevance & Risks in Welding
The increased hardness in the cut edge hardening zone makes the area susceptible to cracks and fractures under mechanical load. This can lead to component failure, especially when the material is stressed under tension.
Workshop Practice & Action Instructions
To minimize the risks of the cut edge hardening zone, controlled cooling should be performed after cutting processes. This can be achieved by using cooling water or cooling oil. The maximum hardness in the hardening zone should be kept below 500 HV to avoid crack formation.