Cut edge microcracking
Microcrack formation occurs during rapid cooling or martensitic transformation at cut edges, which reduces dynamic load capacity.
Physical-Chemical Mechanism of Action
Rapid cooling forms the steel into a glass-hard structure called martensite. This process can cause microscopic cracks at the cut edges because the material structure contracts suddenly and unevenly.
Metallurgical Relevance & Welding Risks
Microcracking increases susceptibility to macroscopic cracks under load. This can lead to component failure or collapse, especially under dynamic load distributions. Additionally, the microcracked zone can reduce toughness and weld strength levels.
Workshop Practice & Action Guidelines
To avoid microcracking, control the cooling rate. This can be achieved by slow cooling after welding or by using cooling blankets. For highly stressed components, it's advisable to carefully select materials and, if necessary, use special welding methods like TIG welding.