Metal Stamping Materials: Properties & Selection Guide

A spring contact stamped from C11000 copper instead of C17200 beryllium copper passes every dimensional check at the press - and fails months later in the field, when the contact has relaxed and the connection runs hot. Material failures on stamped parts are rarely instant; they are thermal, electrical or corrosive, and they surface after the die is cut and the program is committed. The grade on the print is a design decision. This guide gives you the data to make it.

It covers the materials that carry nearly every stamped part program - copper and its alloys, steel and stainless, aluminum, brass and phosphor bronze - with the numbers that decide between them: tensile and yield, conductivity, thermal ceilings, formability in the die, temper behavior, finishing compatibility and cost. The selection logic starts from the function the part performs, not from the material catalog, and it ends with the specification discipline that keeps a good material decision from turning into a field failure.

The process context matters as much as the alloy data. Our plant runs 21 presses to 110 tons, from Aida high-speed lines at up to 300 strokes per minute to 45-110 ton presses for heavier work, on strip from 0.05 to 3.0 mm thick and up to 650 mm wide, with piloted positioning at ±0.005 mm. Material thickness and strip width pick the press before the grade picks the die, so both dimensions belong in the conversation from the first RFQ.

Key takeaways

C11000/C10200 copper carries about 101% IACS conductivity but yields at low stress; C17200 beryllium copper trades conductivity (15-25% IACS) for spring strength up to about 1,300 MPa when aged.
301 stainless spans roughly 515-1,300 MPa tensile depending on temper - the go-to where corrosion resistance and spring behavior meet.
Aluminum 5052 forms tighter radii without cracking than 6061; 6061 gains strength from heat treatment but bends worse.
Strip thickness for copper runs 0.10-2.0 mm, and strip utilization of 60-80% makes material cost an engineering variable, not a fixed line item.

The Selection Logic

Every stamped part performs one of four functions, and the function decides the material. Current-carrying parts optimize conductivity first; spring parts optimize elastic limit; structural parts optimize formability and cost; corrosion-exposed parts optimize the finish route. The mistake that produces most field failures is starting from the material - "we have always used brass" - instead of from the function and its constraints.

Part function	Optimize first	Then check	Typical alloys
Current carrying	Conductivity	Strength against insertion force, temperature rise	C11000, C10200, C19400
Spring / contact	Elastic limit	Conductivity against resistance budget	C17200, 301 SS, C51000
Structural	Formability, cost	Corrosion environment, weldability	SPCC, SECC, 5052, 6061
Corrosion exposed	Finish route	Base alloy compatibility with coating	301/304 SS, SECC, 5052

The order of operations is fixed. Name the function, write the constraint that the function imposes (a resistance budget, a force window, a salt-spray hour target), then let the table below narrow the alloy list. Two parts can be dimensionally identical and demand different materials because the function differs - a current bar and a spring finger in the same connector are rarely the same alloy.

Write the material decision down in the RFQ block before it reaches the supplier. A complete material callout names the grade, the temper, the thickness with tolerance, the finish and its test standard, and the volume band the tooling is sized for. A drawing that says "material per customer standard" or "suitable material" delegates the engineering call to the quoting desk, and the quoting desk optimizes for price. The cost of naming the material is one line of text; the cost of not naming it is a revalidation and a re-tooling downstream.

Mechanical Properties: The Alloy Table

Alloy	Typical tensile (MPa)	Conductivity (% IACS)	Typical stamped part
C11000 ETP copper	200-250 (annealed)	~101	Terminals, busbars
C10200 OFHC copper	200-250 (annealed)	~101	High-purity current paths
C19400 copper-iron	~410-480	~60-65	Lead frames, power terminals
C17200 beryllium copper	up to ~1,300 (aged)	15-25	Spring contacts
SPCC cold-rolled steel	~280-310	n/a	Brackets, shields
SECC galvanized steel	~280-310	n/a	Corrosion-resistant brackets
301 stainless steel	515-1,300 (temper)	~2-3	Springs, EMI shields
304 stainless steel	~515-620 (annealed)	~2.4	Corrosion-resistant parts
5052 aluminum	~195-230	~35	Structural stampings
6061 aluminum	~290-310 (T6)	~43	Heat-treated parts
Brass C26000	300-600 (temper)	~28	Connector shells
Phosphor bronze C51000	330-690 (temper)	~15	Clips, spring contacts
Phosphor bronze C52100	380-800 (temper)	~13	Heavy-duty springs, terminals

How to read the table: strength and conductivity pull in opposite directions. For current-carrying parts, conductivity is the spec and strength is the constraint; for structural parts, formability and finish matter more than conductivity. The two copper rows are the same material at two jobs - C11000 carries current, C17200 carries load. Values are typical published ranges for strip temper; the actual coil is confirmed by the mill certificate at PPAP, never by a table.

Three rows deserve a closer look because they solve the problems the plain alloys cannot. C19400 copper-iron sits between C11000 and C17200: roughly 60-65% IACS conductivity with tensile near 410-480 MPa in worked tempers, which is why it dominates lead frames and power terminals that must carry current and hold shape. C52100 is the higher-tin phosphor bronze, stronger and harder than C51000 with slightly lower conductivity, used where a spring must survive more cycles or run hotter. 304 stainless is the general-purpose corrosion grade where 301 is the spring grade - same family, different jobs, and the drawing has to say which.

The selection logic goes further than the table. Current-carrying parts optimize conductivity, then check strength against insertion force; spring parts optimize elastic limit, then check conductivity against the resistance budget; structural parts optimize formability and cost, then check the corrosion environment. Start from the function, not from the material.

Thermal and Electrical Limits

Every stamped part lives under a thermal budget, and the budget differs by alloy:

Copper melts near 1,083 C, but that number is not the constraint - C11000 anneals and softens far below its melting point. Continuous service above roughly 150-200 C relaxes a copper spring contact and raises contact resistance. For spring duty, C17200 is aged to peak strength and holds it where C11000 would yield.
301 stainless keeps useful strength far beyond copper's limit and does not soften through solder reflow - a lead-free reflow peaks near 245-260 C - which is why it shows up in high-temperature connectors, shields and spring fingers.
Aluminum (5052/6061) melts near 600-650 C and loses strength well below that - fine for structural stampings, wrong for hot environments. 6061-T6 over-ages above roughly 175 C sustained, and the strength loss is permanent.
Plating processes add their own thermal and chemical budget. Reel-to-reel selective plating - gold, silver, tin or nickel - runs in strip form, and the base alloy must survive the plating line without distortion. That is another reason 0.10 mm copper stock is plated as a coil, not as loose parts.

Thermal limits also decide the assembly route: a tin-plated busbar solders at a lower temperature than a silver-plated one, and the alloy's softening point sets the ceiling for the whole assembly process. For hot environments, 301 stainless or beryllium copper is the standard answer; annealed copper should not be specified there at all.

Two secondary thermal effects are worth writing into the design review. First, coefficient of thermal expansion: a stamped contact overmolded in plastic or potted in an assembly moves with temperature, and a CTE mismatch between a copper alloy (about 17 x 10-6 /K) and the surrounding material can relax or over-stress the interface over thermal cycling. Second, current density: a busbar or terminal sized for 20 A at 20 C may exceed its allowed temperature rise at 85 C ambient because resistance rises with temperature - the material choice and the cross-section have to be checked together against the operating temperature.

How Alloys Behave in the Die

Formability is where material selection meets the tool, and the behavior differences below are the reason a material change after the die is cut is a tooling change.

Alloy	Springback	Die wear	Tight radii	Galling risk
C11000 annealed copper	Low	Low	Excellent	Low
C17200 beryllium copper	High	High	Good in soft temper	Low
301 stainless	Very high	Very high	Poor in hard tempers	Moderate
SPCC / SECC steel	Low-moderate	Moderate	Good	Low
5052 / 6061 aluminum	High	Low	5052 good, 6061 poor	High
C26000 brass	Moderate	Moderate	Good	Low
C51000 / C52100 bronze	Moderate-high	Moderate	Good	Low

Springback. Every alloy springs back after bending. Annealed copper is dead-soft and takes a bend; 301 stainless and C17200 spring back hard. The die compensates by over-bending in the form tooling - which is why a material change after the die is cut is a tooling change.
Die wear. 301 stainless and beryllium copper wear tool steel faster than aluminum or copper. Die maintenance intervals - and the per-part cost they add - differ by alloy.
Tight radii. Aluminum cracks at tight bend radii, 5052 less than 6061. Copper and brass bend to much smaller radii. Bend allowance is computed at the die design stage from the actual temper, not from a generic table.
Burrs. Burr height tracks material hardness and die clearance. On thin strip (0.10 mm), a burr is not cosmetic - on a plated contact it is a plating defect and a reliability issue, so clearance and die maintenance are set per material.

Strip surface and lubrication finish the picture: a clean, consistent coil keeps die wear predictable and plating adhesion uniform, while inconsistent lubrication shows up as variable bend angles and burr. That is why coil certification - surface, thickness, temper - is part of the material spec, not a warehouse detail.

Temper: The Fourth Material Dimension

Grade alone does not define the part; temper does. The same C11000 strip behaves differently annealed, half-hard or full-hard, and the same logic applies to brass, bronze, aluminum and stainless:

Worked temper numbers make the point concrete. The table below shows typical published values for C11000 strip across its temper ladder; the pattern - strength up, elongation down, springback up - repeats for every work-hardening alloy.

C11000 strip temper	Typical yield (MPa)	Elongation (%)	Forming note
Annealed (O)	~70	~45	Dead soft, deep forms, no spring strength
Half-hard	~210-250	~15-20	General terminals, some spring hold
Full-hard	~310-345	~4-8	Stiff parts, limited bendability

Springback and bendability move with temper: harder tempers spring back more and bend to larger minimum radii, so the form tooling is compensated for the temper on the print.
Strength climbs with temper - a half-hard copper strip roughly doubles the yield of the annealed coil, which is the difference between a contact that holds and one that relaxes.
Consistency. A coil that varies in temper across its length stamps parts that pass dimensional checks but drift in spring force - the failure mode that shows up in the field, not at the press. Specify a temper range and verify it per lot.
Cost follows: temper-controlled coils carry tighter mill certification, and the premium is small against the cost of a die rework. Specify the temper in the RFQ, and confirm it in the PPAP material certificate.

The temper nomenclature is worth knowing because it appears on every drawing and certificate. Copper and its alloys use the O (annealed) and H (worked) series - half-hard is commonly H01/H02 territory depending on the standard - while aluminum uses O, H1x (strain-hardened), and T (heat-treated) designations such as T6. Stainless uses its own annealed, 1/4-hard to full-hard ladder. Whatever the family, the rule is the same: name the temper, order the temper, verify the temper, and design the die for that temper.

Ordering strip for a stamped program is a five-line spec, not a grade name. Line one: grade and temper. Line two: thickness with tolerance - at 0.10 mm strip, a thickness tolerance of plus or minus 0.005 mm changes the forming and the contact force. Line three: width and edge condition (slit edge versus mill edge). Line four: surface finish class - a 2B or equivalent finish for parts that will be plated or seen, with the scratch limits written down. Line five: coil weight and packaging, because a coil change in mid-run is a process interruption and a potential material-lot discontinuity. A material spec that carries all five lines quotes the same way twice in a row; a spec that names only the grade quotes differently every time.

Corrosion and Finishing Compatibility

The finish is part of the material decision, because the base alloy decides which finish routes are even available. The table below is the pairing map that belongs in every drawing review.

Base material	Finish route	Typical thickness	Verification
Copper alloys	Selective reel-to-reel gold, silver, tin, nickel	2-8 µm	X-ray thickness, adhesion, salt spray
Steel (SPCC)	Zinc plating, powder coat, E-coat	Zinc 5-12 µm	Salt spray per ASTM B117
Galvanized steel (SECC)	As-supplied, plus paint where needed	Coil-applied zinc	Coating weight per lot
Aluminum	Anodize, conversion coating	5-25 µm anodize	Coating thickness, salt spray
Stainless	None required in most environments	n/a	Surface finish class

Three rules govern the pairing. First, plating does not fix a bad base alloy: a tin layer on copper that relaxes under load still relaxes - the spring behavior belongs to the base metal. Second, the plating callout has to name thickness, location and test: "gold plated" with no number is not a specification, and the terminal plating guide covers the full gold, silver, tin and nickel selection logic. Third, salt-spray hours per ASTM B117 are the acceptance metric for corrosion claims - 168 hours and 500 hours look identical on the shelf and fail differently in the field, so the drawing names the hours. The plating and surface finish guide carries the complete finish selection framework.

Manufacturing and Cost Reality

The material decision is also a cost and process decision, and the numbers are concrete:

Strip thickness. Copper strip runs 0.10-2.0 mm; steel and aluminum run comparable bands for progressive work. Thicker stock pushes the program toward 110-ton presses and slower speeds.
Strip width. Our lines accept strip to 650 mm wide. Width drives layout efficiency: a layout that fits two parts across instead of one doubles utilization on the same press hour.
Utilization. Strip layout targets 60-80% utilization - the difference between a good layout and a poor one is measurable scrap cost over millions of parts.
Press selection. Thin strip (0.10-0.5 mm) feeds high-speed lines at up to 300 SPM; 1.5-3.0 mm stock moves to 45-110 ton presses at lower speeds. The same alloy at 0.15 mm and 1.5 mm is two different programs - thickness picks the press before the grade picks the die.
Plating compatibility. The alloy decides which plating route is available, and the terminal plating guide covers gold, silver, tin and nickel selection in detail.
Volume economics. Stamping beats machining from roughly 50,000 pieces per year, so material and tooling decisions assume that volume band; the stamping tooling cost guide works the amortization arithmetic.
The die is built around the material. Springback compensation and station layout are set during tool and die design; change the alloy after the die is cut and you are buying a new die.

One more manufacturing reality: the coil is the raw material, and coil quality shows up in the parts. Surface scratches and rolling marks on the incoming strip become rejects on plated or cosmetic parts; thickness variation across the strip width becomes bend-angle and flatness drift; edge slivers become die damage. A supplier that checks coil surface, thickness and temper at receiving - and documents it per lot - is running a material system, not a warehouse.

Material choice also sets the inspection plan: conductivity parts get resistance and plating-thickness checks, spring parts get force and relaxation checks, structural parts get dimensional and surface checks - the spec decides the test. A 5052 bracket and a C17200 spring from the same supplier run through different gauges, and the control plan should say so.

Material Change Control and Certification

A mid-program material change - a different coil supplier, a different temper - is a revalidation event under IATF 16949:2016, not an administrative swap. Springback shifts, bend angles move, and the change has to be documented through PPAP. Lock the grade, temper and coil spec on the print, and treat any deviation as a change request with evidence. The IATF 16949 guide for metal stampers explains what the certification actually requires of the material system.

Mill certificates. Expect EN 10204 3.1 documentation tying each coil to its heat number and chemical analysis. The certificate is the traceability spine of the whole program.
Per-lot verification. Temper and thickness are verified at receiving, not assumed from the label. A coil that drifts in temper stamps parts that drift in spring force.
PPAP evidence. The material certificate, the capability study and the FAIR dimensional data travel together; if the material changed between PPAP and production, the PPAP is void.

Common Selection Mistakes

Four failure patterns account for most material-driven stamping problems, and each one was a design decision before it was a field failure.

Copper where a spring is needed. C11000 passes every dimensional check and relaxes under load. The fix is C17200 or a hard-tempered bronze - elastic limit, not conductivity, decides spring parts. See the spring contact stamping guide.
6061-T6 with a sharp radius. The drawing demands a 0.5x thickness bend in T6 material; the part cracks at the bend line. The fix is 6061-O formed and aged, or 5052-H32, or a larger radius - decided before the die is cut.
Material change after tooling. A coil supplier change or a "like for like" substitution shifts springback, and the die was compensated for the original temper. The fix is the revalidation gate described above, with tryout evidence.
Finish specified, base alloy ignored. A zinc finish on SPCC passes salt spray for a while and fails where the coating is cut; a galvanized SECC base with the same finish survives the same test. The corrosion budget belongs to the base metal plus the finish, not the finish alone.

The deeper guides on the material families carry the alloy-by-alloy detail: copper stamping alloys, phosphor bronze stamping, stainless steel stamping, steel stamping parts and stamped aluminum parts.

Data to Spec

A material spec written as "copper" instead of "C11000, half-hard, 0.5 mm" invites the supplier to make the engineering call for you - and the failure lands in the field, not on the quote. Every downstream process, from die to plating to assembly, is locked to the grade on the print. Name the function, name the grade and temper, name the finish and its test, and the material decision stops being a guess.

Send us your material spec for a DFM review within one business day.