Official Answer
Answer
In nested wave springs, the layers slide against each other during deflection. If the surfaces are rough or lubrication fails, 'Inter-turn Friction' generates localized heat and galling. This friction increases the effective stress on the outer fibers of the material. A fracture in a single turn of a nested spring typically shows 'beach marks' characteristic of fatigue, originating from a site of surface galling. Troubleshooting involves: 1) Improving the surface finish of the flat wire during drawing. 2) Applying a high-pressure lubricant. 3) Reducing the number of nested turns and increasing the material thickness of each turn to achieve the same rate with fewer sliding interfaces.
