Bending fatigue strength
Bending fatigue strength is the measure of the allowable alternating stress under pure bending load over a certain number of load cycles. It indicates how many times a material can be flexed before it suddenly breaks.
Physicochemical mechanism of action
Bending fatigue strength refers to the alternating stress on a material from repeated bending. Each bend causes microcracks that grow with each subsequent load cycle. When these cracks become too severe, sudden fracture occurs.
Metallurgical relevance & risks in welding
When welding steels, bending fatigue strength is especially important. Excessive heat treatment or insufficient cooling can alter the microstructure and reduce fatigue strength, leading to sudden cracks. This is particularly dangerous in dynamic applications like machine parts or vehicle components.
Workshop practice & instructions
To maintain bending fatigue strength during welding, pay attention to the following:
• Use correct heat treatment parameters (temperature and time).
• Ensure proper cooling to achieve a homogeneous microstructure.
• Avoid excessive stresses by careful planning of welding processes.