Metal Stamping Materials: Properties That Decide How a Part Forms
Material sets what shapes are possible, how tight a bend can be, how much force the press needs and how long the die lasts. Here are the common stamping materials and the properties that matter.
Common stamping materials
Typical grades and thickness ranges shops run most often, not machine limits. Grade names in brackets are the Japanese and European near equivalents.
| Material | Typical grades | Typical thickness | Formability | Springback | Notes |
|---|---|---|---|---|---|
| Cold rolled steel | 1008, 1010 (SPCC, DC01) | 0.4 to 6 mm | High | Low | The default for brackets and covers. Needs oil, plating or paint against rust. |
| Hot rolled pickled | HRPO, A1011 | 1.5 to 8 mm | Medium | Low | Heavier parts. Rougher surface and looser thickness tolerance than cold rolled. |
| Galvanized steel | G60, G90 (SGCC, DX51D) | 0.4 to 3 mm | Medium | Low | The sheared edge is bare. The coating can flake at tight bends and burn off at welds. |
| HSLA steel | Yield 340 to 550 MPa | 0.8 to 6 mm | Medium to low | High | Allows a thinner, lighter part. Needs more tonnage and wears tools faster. |
| Stainless 301 | 1/4 to full hard | 0.1 to 2 mm | Medium | High | Work hardens and holds spring temper. Used for clips and contacts. |
| Stainless 304 | 304, 304L, 316 | 0.3 to 3 mm | High when annealed | Medium | Work hardens and galls. Needs about 1.5 times the tonnage of mild steel. |
| Stainless 430 | Ferritic, magnetic | 0.4 to 3 mm | Medium | Medium | Lower nickel cost. Less ductile than 304, so deep draws are harder. |
| Aluminum 3003, 5052 | H14, H32 | 0.5 to 4 mm | Good | Medium | Soft and light. Scratches and galls, and leaves fine slivers at the cut edge. |
| Aluminum 6061 | T4, T6 | 0.5 to 4 mm | Low in T6 | Medium to high | Cracks on tight bends in T6. Form in T4 or annealed, then age to T6. |
| Copper | C11000 | 0.1 to 3 mm | High | Low | Best conductivity. Soft, so it marks easily. Used for busbars and contacts. |
| Brass | C260 (cartridge brass) | 0.1 to 2 mm | High | Medium | Terminals and drawn shells. Stress relief after deep drawing prevents season cracking. |
| Phosphor bronze | C510 | 0.1 to 1.5 mm | Medium | Medium to high | Springs and contacts that flex many times without fatigue. |
| Beryllium copper | C172 | 0.05 to 1 mm | Medium when annealed | Medium | Highest strength of the copper alloys after aging. Needs handling controls. |
| Spring steel | 1074, 1095 | 0.2 to 2 mm | Low | High | Formed soft and then heat treated, or bought pre-hardened for simple bends. |
Properties that decide stampability
Ten properties explain most stamping problems. A shop that asks about them early is reading your part, not just pricing it.
- Elongation and n valueElongation is how far the metal stretches before it cracks. The n value says how evenly it thins when stretched. Both matter most in drawing and forming.
- r valueResistance to thinning while the sheet is drawn in. A higher r value draws deeper cups, which is why drawing quality steel is sold on it.
- Yield to tensile ratioA low ratio gives a wide margin between the start of forming and fracture. High strength alloys have little margin and crack sooner.
- Work hardeningMetal gets harder and stronger as it is formed. Stainless 304 and 301 harden quickly, so later stations need more force and sometimes an anneal.
- SpringbackBent metal opens partly after the die lifts. It grows with strength and shrinks with stiffness, so HSLA, stainless and aluminum spring back more than mild steel. The die bends past the target angle to compensate.
- Grain directionRolled sheet bends better across the rolling direction than along it. Ask the shop to run bend lines across the grain on tight bends.
- Temper and hardnessThe same alloy comes soft or hard. Hard tempers need larger radii and more tonnage and crack more easily.
- Coating and surfaceZinc, tin and nickel layers can crack or smear. Surface finish carries through the stamping, so cosmetic parts need clean strip and protected handling.
- Thickness tolerance and flatnessCoil set, camber and thickness variation change how a die performs. Precision strip costs more and holds both tighter.
- Tool wear and burrAbrasive and hard materials dull cutting edges faster and raise burr height. Mill scale on hot rolled steel does the same.
Typical minimum inside bend radius
For a 90 degree bend with the bend line across the rolling direction. The low end is for soft temper. Harder tempers, thicker stock and bends along the grain need more.
These are starting points. The shop confirms the radius for your grade, temper and thickness before it cuts the die.
| Material | Typical minimum radius |
|---|---|
| Cold rolled steel | 0.5 to 1 times thickness |
| HSLA steel, 340 to 550 MPa yield | 1.5 to 3 times thickness |
| Stainless 304, annealed | 1 times thickness |
| Stainless 301, by temper | 1 to 3 times thickness |
| Aluminum 5052-H32 | 1 to 2 times thickness |
| Aluminum 6061-T6 | 2.5 to 4 times thickness |
| Brass C260, half hard | 1 times thickness |
| Phosphor bronze, by temper | 1 to 3 times thickness |
| Spring steel, annealed | 1 to 3 times thickness |
Choosing a material by requirement
Start from what the part has to do. The print can then name a grade or a performance and let the shop propose an equal.
- Electrical conductivityCopper, brass, phosphor bronze or beryllium copper. Pick by how much spring the part needs.
- Corrosion resistanceStainless 304 or 316, aluminum or coated steel. Coated steel leaves a bare sheared edge.
- Spring behaviorStainless 301, phosphor bronze, beryllium copper or spring steel, depending on temperature, cycles and cost.
- Lowest piece priceCold rolled steel with a plated or painted finish, unless the part has to survive its environment bare.
- Low weightAluminum 5052 for formed parts. HSLA steel when the part has to stay steel but can go thinner.
- Washdown and food contactStainless 304 or 316, with a surface finish and a weld process that the application allows.
Thickness variation changes how a die runs. Read about coil thickness and width tolerance.
Frequently asked questions
Can any metal be stamped?
Most sheet and strip metals can, as long as they are ductile enough for the operation. Brittle alloys crack in bending and hard tempers limit how tight a bend can be. Ask the shop to check the grade and temper against the shape of your part.
Which material is the least expensive to stamp?
Cold rolled steel, in most cases. It forms easily, wears tools slowly and is widely stocked. Piece price also depends on strip use and secondary operations, so a more expensive alloy can win on a part that nests well.
Why does my aluminum part crack at the bend?
Usually the temper is too hard for the radius. Aluminum 6061 in T6 cracks on tight bends. Switch to 5052 in H32, or increase the inside radius. 6061 can be formed in T4 or annealed and aged afterward.
Keep reading
- Steel Grades for Stamping: How Cold Rolled, HSLA and Spring Steel Behave in the Die
- Stainless Steel Stamping: Choosing Between 301, 304 and 430 for a Stamped Part
- Aluminum Stamping Alloys: Choosing Between 3003, 5052 and 6061 for Stamped Parts
- Copper, Brass and Phosphor Bronze for Stamping: Picking the Alloy, Temper and Strip Spec
- Beryllium Copper Stamping: Choosing a Temper, Planning the Heat Treat and Handling It Safely
- Pre-Plated Strip or Plating After Stamping: How Cut Edges, Forming and Cost Decide
- Stamping material sourcing and coil supply
- Stamping processes and die types
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