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How to solve the problem of large stamping rebound of stainless steel strip
source：www.paybx.cn | Release time：2026年09月01日1. Reasonably reduce the hardness of materials
For the same grade, the lower the hardness, the higher the elongation, and the smaller the rebound.
Example: The original rebound of 301-3/4H was too large. If conditions permit, it can be changed to 301-1/2H, and the rebound will significantly decrease; The cost is a decrease in elasticity, and it is necessary to verify the elasticity indicators of the product.
We cannot blindly choose high hardness, but select feasible hardness under the premise of satisfying elasticity.
2. Brand replacement evaluation
Same hardness condition: 301 rebound>304; If the product has sufficient elasticity margin, it can be evaluated to replace 301 with 304. The rebound will be smaller, but the elasticity will decrease.
3. Control residual stress in incoming materials
The residual stress caused by rolling and slitting can lead to drift and warping of the rebound angle of the parts.
Require suppliers to have good steel strip shape and reduce sickle bending and wave shapes;
Hard shrapnel material, avoid using eccentric materials with high residual stress;
If conditions permit, stress relief annealing (low-temperature stress relief) can be performed, but it is important to note that excessive annealing should not cause a decrease in hardness.
It is not recommended to use soft ANN directly: the rebound is very small, but there is almost no elasticity, and the shrapnel directly fails.
2、 Mold design compensation (most commonly used, core means of mass production)
1. Angle compensation (over bending compensation)
When bending, adjust the bending angle of the mold to a negative angle (over bending) and use rebound to restore it to the design angle.
1/2H 301: Generally pre bent 3 ° -8 °
3/4H/H full hardness: greater rebound, pre bending 8 ° -15 °
Actual values need to be corrected through trial modeling; The thicker and harder the material, the greater the compensation angle.
2. Bending R-angle optimization
The smaller the R, the higher the proportion of local plastic deformation and the smaller the rebound; But if R is too small, it will cause cracking on the outer side.
Hard stainless steel bending inner R ≥ 1.5-2t (t=material thickness), cannot blindly reduce R.
3. Convex die pressing and upsetting method (strong pressing process)
At the end point of the bend, apply forced upsetting pressure to the rounded corner area of the bend to allow for sufficient plastic deformation and reduce elastic recovery.
Suitable for thin steel strips with shrapnel; Be careful not to apply excessive pressure to prevent thinning or fracturing of parts.
4. Adjustment of mold gap
The gap between stainless steel stamping dies should not be too large: if the gap is too large, the material will be less stretched, the elastic components will be more abundant, and the rebound will be intensified.
Reasonable gap: 1.0-1.1 times the material thickness; The lower limit for hard materials is taken, and if the gap is too large, the rebound will significantly increase.
5. Increase the compression force and compression reinforcement
The pressing plate compresses the billet, reduces material sliding in the bending area, and prevents warping, twisting, and rebound; Bullet molds must be reliably pressed.
6. Product structure optimization (product side redesign, prioritize communication with customers)
(1) Add reinforcing ribs, compression grooves, and compression ribs to the bending position to change the stress distribution and prevent rebound and warping;
(2) Avoiding cantilever long bending structures makes it difficult to control the rebound of long cantilevers;
(3) Multi pass bending to avoid large angle bending.
3、 Adjustment of stamping process parameters
1. Stamping speed
Hard stainless steel should not be too fast, and the stamping speed should be appropriately reduced to achieve more complete plastic deformation and slightly improve rebound; Excessive speed can lead to stress concentration.
2. Process splitting to avoid one-time molding
Do not bend large angle and complex fragments in one step; Adopting step-by-step bending and multi-step gradual forming to reduce the amount of single rebound.
3. Avoid repeated bending multiple times
Repeated bending will continue to work harden, with increasing rebound and easy fracture.
4、 Rebound has occurred, subsequent remedial measures will be taken
1. In mold calibration steps: Add a calibration station after molding to forcibly calibrate the angle inside the mold; High production efficiency.
2. Manual calibration after molding: suitable for small batches; Not recommended for large quantities, manual correction can cause angular dispersion and change local hardness, resulting in decreased fatigue performance.
Try not to rely on manual angle bending of spring components, as stress relaxation and angle drift may occur during use.
5、 Misconceptions that are prone to pitfalls
1. Relying solely on increasing over bending compensation and ignoring material hardness fluctuations: If there is a large fluctuation in HV within the same batch, some may be qualified while others may exceed the tolerance.
The incoming materials must be controlled within the HV hardness range, and the hardness range must be narrowed.
2. The gap between the molds was adjusted too large in an attempt to protect the molds, resulting in uncontrolled rebound.
3. There are microcracks at the edges of the strip, and in order to reduce rebound, the bending R is forcibly reduced, resulting in direct bending and cracking.
The edges must be finely cut without cracks.
4. I hope to manually calibrate the mass-produced shrapnel afterwards: later use may cause angle drift and fatigue fracture.
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