The Requirements For Stamping Materials Are

The surface and internal properties of stamping sheets have a great influence on the quality of stamped products. The requirements for stamping materials are:
①The thickness is precise and uniform. Stamping molds are precise and have small gaps. Excessive thickness of the sheet will increase the deformation force, cause material jamming, and even cause the die to burst. Too thin a sheet will affect the quality of the finished product, and may even cause cracks during deep drawing.
②The surface is smooth and clean, without spots, scars, scratches, surface cracks, etc. All surface defects will remain on the surface of the finished workpiece, and crack defects may expand deep and wide during bending, drawing, forming and other processes, resulting in scrap.
③The yield strength is uniform and has no obvious directionality. Anisotropy (see plastically deformed sheets during the stamping process such as drawing, flanging, bulging, etc., due to the occurrence of anisotropic yielding in sequence, the amount of plastic deformation is inconsistent, which will cause uneven deformation and inaccurate forming. Defective or scrap products.
④High uniform elongation. In the tensile test, the elongation before the necking phenomenon begins to appear on the sample is called the uniform elongation. During deep drawing, the deformation of any area of the sheet cannot exceed the uniform extension range of the material, otherwise uneven deformation will occur.
⑤The ratio of yield to strength is low. The ratio of the material's yield limit to its strength limit is called the yield-strength ratio. A low yield-to-strength ratio can not only reduce deformation resistance, but also reduce the tendency of wrinkling during deep drawing, reduce the amount of rebound after bending, and improve the accuracy of bent parts.
⑥ Low work hardenability. The work hardening that occurs after cold deformation will increase the deformation resistance of the material and make continued deformation difficult, so plates with low hardening index are generally used. However, materials with a high hardening index have good plastic deformation stability (that is, the plastic deformation is relatively uniform) and are less prone to local cracking.
In actual production, process tests similar to the stamping process, such as deep drawing performance tests, bulging performance tests, etc., are commonly used to test the stamping performance of materials to ensure the quality of finished products and a high pass rate.