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　　1. Precise and uniform thickness. Stamping with precision molds, small gap, sheet thickness will increase the deformation force, and cause jamming, and even the concave mold expansion; sheet too thin will affect the quality of the finished product, and even cracking in deep drawing.

　　2, the surface is clean, no spot, no scar, no abrasion, no surface cracks. All surface defects will remain on the surface of the finished workpiece, crack defects in the bending, deep drawing, molding and other processes may be extended to the deep and wide, resulting in scrap.

　　3, yield strength uniformity, no obvious direction. Anisotropy (see plastic deformation of the sheet in the deep drawing, flanging, expanding the shape of the stamping process, due to the emergence of all directions of yielding successively, the amount of plastic deformation is inconsistent, will cause uneven deformation, so that the molding is inaccurate, resulting in substandard or scrap.

　　4、High uniform elongation. Tensile test, the specimen began to appear before the phenomenon of thin neck extension rate is called uniform elongation. In deep drawing, the deformation of any area of the sheet can not exceed the uniform extension range of the material, otherwise there will be uneven deformation.

　　5, low yield-strength ratio. The ratio of the yield limit of the material to the strength limit is called the yield strength ratio. Low yield-to-intensity ratio not only reduces the deformation resistance, but also reduces the tendency to wrinkle when deep drawing, reduces the amount of rebound after bending, and improves the accuracy of the bent parts.

　　6, low work hardening. Cold deformation after the emergence of hardening will increase the deformation resistance of the material, so that continue to deform difficult, so generally use low hardening index of the plate. However, the hardening index of the material with high plastic deformation stability (i.e., plastic deformation is more uniform), not easy to appear localized cracking.