The Main Material Properties in Metal Stamping

Through stamping, we can obtain parts with the desired dimensions and shapes. During the stamping process, factors such as product quality, processing efficiency, and die life must be considered. Different materials have different properties. The main properties that affect material formability are: yield strength, tensile strength, ductility, and flowability. Among these, yield strength determines the start of forming, while tensile strength, ductility, and flowability influence the forming outcome. This article will help you understand these properties in more detail.

Yield Strength

Yield strength refers to the minimum stress required for a material to undergo permanent deformation. If the stamping stress does not reach this minimum, the material will only deform elastically and will spring back, resulting in failed forming. It is worth noting that even after forming, the material may experience partial springback after being removed from the die if some local areas did not reach the required stress. Therefore, when designing dies, springback compensation (estimating the springback value to adjust target dimensions) or additional forming steps are sometimes incorporated.

Tensile Strength

Tensile strength refers to the maximum stress a material can withstand before fracture. When stamping materials with high yield strength, high pressure is often required, but more pressure is not always better. Without understanding the tensile strength, the finished product may crack.

Ductility

Ductility refers to the ability of a material to undergo deformation before fracturing, and it relates to the complexity of forming the material. In theory, stamping can proceed smoothly when the applied pressure is greater than the yield strength but less than the tensile strength. However, if the material has poor ductility, local stresses may exceed the tensile strength, ultimately causing cracking.

Formability

Material flow refers to the ability of a material to deform smoothly and efficiently during forming. It relates to the uniformity and ease of material shaping. When forming requirements are met, better flow ensures more even stress distribution, resulting in improved forming quality, such as dimensional accuracy and surface finish. At the same time, the stress on the mold is more even, which is very beneficial for the mold.

Overall, having a certain understanding of the material helps in selecting the appropriate press and die. However, if the material has very high yield strength, direct stamping can cause significant damage to the die, and the finished product may crack or even fail to form. Heating the material to a high temperature can reduce its yield strength and improve its flowability and ductility, enabling efficient stamping—this is known as hot forming.

If you have any questions, or interested in hot forming stamping production lines, you can contact us. Thank you for reading.