1. Radius of bending part. When the spring piece is formed, most of them need to be bent. If the radius of curvature of the curved parts is relatively small, these parts will generate a large stress. Therefore, if it is necessary to avoid large stress at the bending part, the bending radius shall be at least five times of the plate thickness during design.
2. Stress concentration at notch or hole. The spring piece often has stepped parts and openings, and stress concentration will occur at the step where the size changes sharply. The smaller the diameter of the hole and the larger the plate width, the greater the stress concentration coefficient.
3. Shape and dimension tolerance of spring plate. The leaf springs are mostly processed by stamping. In the design, the shape and size suitable for stamping shall be considered. At the same time, the dimensional tolerances such as springback during bending and deformation during heat treatment shall be fully considered.
The requirements for heat treatment of spring sheet shall be put forward according to the service performance requirements. The hardness after heat treatment can generally be determined between 36 ~ 52hrc.