The basic requirements of metal stamping materials mainly involve mechanical properties, process performance, and economic aspects, to ensure smooth stamping operations and the quality of final products. The specific requirements are as follows:
- Good Plasticity
- High elongation (δ) and reduction of area (ψ): The material should have strong plastic deformation ability to avoid cracking during stamping. Metals with good plasticity, such as low-carbon steel, aluminum, and copper, are commonly used.
- Uniform elongation: The material should deform uniformly during stretching to avoid premature localized necking.
- Appropriate Strength and Hardness
- Low yield strength (σs) and tensile strength (σb): Materials with lower strength are easier to form, reducing mold wear and equipment energy consumption.
- Moderate hardness: Excessive hardness shortens die life, while too low hardness may affect the rigidity of parts.
- Uniform Thickness and Structure
- Small thickness tolerance: Uneven thickness can cause uneven forming, wrinkling, or cracking.
- Uniform microstructure: Internal inclusions, porosity, or segregation must be avoided, as they may lead to defects during stamping.
- Good Surface Quality
- Smooth surface without defects: Scratches, scale, or rust can affect the surface quality of stamped parts and even damage molds.
- Lubrication performance: The surface should allow lubricant adhesion to reduce friction and mold wear.
- High n-value (strain hardening exponent)
- A high n-value means the material hardens uniformly during plastic deformation, reducing risks of localized thinning and fracture (especially in deep drawing).
- High r-value (plastic strain ratio)
- A high r-value reflects the material’s resistance to thickness-direction deformation. Materials with high r-values (e.g., aluminum-killed steel) are favorable for deep drawing, improving forming stability.
- Low Anisotropy
- Consistent performance in the plane direction: Prevents “earing” defects (uneven edges) caused by anisotropy in stamped parts.
- Good Spring-back Control
- Moderate elastic modulus (E): Materials with lower spring-back (e.g., high-strength steels require special treatment) are easier to maintain dimensional accuracy after forming.
- Economy and Weldability
- Low cost and easy availability: For example, ordinary cold-rolled steel sheets are more economical than stainless steel.
- Compatibility with subsequent processes: If welding or coating is required, the material should possess the corresponding properties.
Typical Metal Stamping Materials Examples
- Low-carbon steel (e.g., SPCC, 08Al): Good plasticity, suitable for general stamping.
- Stainless steel (e.g., 304): Requires high-tonnage equipment; spring-back must be controlled.
- Aluminum alloys (e.g., 5052, 6061): Lightweight and preferred for weight reduction, but prone to galling.
- Copper and copper alloys (e.g., H62): Excellent electrical conductivity, used in electronic components.
Dowell Metal Fab Tech is a professional metal fabrication factory. We can choose a suitable material for your project. Please don’t hesitate to contact us now.