Stainless Steel 304Cu
GB 304Cu · UNS S30430-like, S30430
304Cu (UNS S30430) is a copper-bearing austenitic stainless based on 304, alloyed to lower the work-hardening rate during severe cold work.
Values for the Annealed condition
304Cu tempers and conditions
304Cu is supplied in 4 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault solution annealed (soft) cold-heading wire/rod | Default stock condition for cold heading, riveting and deep drawing where maximum ductility is needed. | 210 | 500 | 55 | 145 HB | — |
drawn wire/bar (light to medium draw) | Pick for wire and bar that must hold size and give higher strength while still allowing moderate forming or threading. | 520 | 700 | 22 | 20 HRC | — |
Quarter hard | Use when a modest strength increase is needed but the part still has to be bent or roll-formed. | 550 | 860 | 12 | 25 HRC | 2.4 % IACS |
Half hard | Choose for springy clips and flat parts needing high strength with only gentle bends. | 760 | 1,030 | 8 | 32 HRC | 2.4 % IACS |
Supply forms, finishes and certifications
Ways 304Cu is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Cold Headed | As-formed fastener | Surface finish |
What is 304Cu?
304Cu (UNS S30430) is a copper-bearing austenitic stainless based on 304, alloyed to lower the work-hardening rate during severe cold work. Annealed material gives 210 MPa yield, 500 MPa tensile, 55 % elongation and 145 HB (78 HRB) with a formability score of 95, and it is supplied as wire, bar and sheet in annealed, cold drawn, 1/4 hard, 1/2 hard and cold-headed conditions for fasteners and deep-drawn shells. Maximum service temperature is 750 °C; copper widens the solidification range so weld procedures need care, and 305 is the nearest alternative when a copper-free chemistry is specified. 304Cu has a density of 7.93 g/cm³ (0.286 lb/in³), heavier than 77% of stainless steel grades. It melts at 1,400°C (2,552 °F). 304Cu has a yield strength of 210 MPa (30.5 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 100% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 193 GPa (28 Msi).
What is 304Cu used for?
- Cold-headed screws and bolts
- Drawn enclosures
- Cookware liners
- Stainless rivets
- Deep-drawn cups and shells
- Sink bowls
- Appliance panels and trim
Advantages
- Forms and bends easily — 95/100, better than 99% of stainless steel grades
- Ductile — tolerates forming and impact — 55%, better than 97% of stainless steel grades
- Polishes to a fine finish — 82/100, better than 95% of stainless steel grades
Limitations
- Low strength — 210 MPa (30.5 ksi), worse than 100% of stainless steel grades
304Cu properties
Typical room-temperature values for 304Cu-Annealed; bars are the position among stainless steel grades.
Physical3
304Cu has a density of 7.93 g/cm³ (0.286 lb/in³), heavier than 77% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical14
304Cu has a yield strength of 210 MPa (30.5 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 100% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
304Cu is rated for continuous service to 750°C (1,382 °F). It conducts heat at 16.2 W/m·K (9.36 BTU/hr·ft·°F), better than 64% of stainless steel grades. Thermal expansion is 17.3 µm/m·K (9.61 µin/in·°F).
Electrical3
304Cu conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 52% of stainless steel grades.
Sustainability4
Producing a kilogram of 304Cu takes about 55 MJ of energy and emits 4.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 65%.
Manufacturability7
304Cu's machinability is fair (42/100, better than 79% of stainless steel grades); weldability very good (72/100); formability excellent (95/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. 304Cu is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 304Cu
Is 304Cu easy to machine?
Gummy and work-hardening like 304 — use sharp, positive-rake carbide, heavy feed, rigid setup and flood coolant; avoid dwelling to prevent a hardened skin.
Can 304Cu be welded?
Weldable by GTAW/GMAW/resistance methods with 308L filler; keep heat input low and avoid hot-crack-prone dilution because copper widens the solidification range.
Can 304Cu be formed, bent or molded?
Excellent for multi-station cold heading, upsetting and deep drawing thanks to the low work-hardening rate; anneal between severe reductions and use chloride-free lubricants.
Manufacturability
The process limits FabDigit applies to 304Cu. Every 304Cu part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair42 / 100 |
|---|---|
| ISO material group | M.1 |
| Cutting speed (rough / finish) | 150 / 180 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Excellent95 / 100 |
|---|---|
| Weldability | Excellent72 / 100 |
| Bendable | Yes |
304Cu chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Csome mills hold ≤0.06 for better formability | ≤ 0.08 | 0.05 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 2 | 1.2 |
| P | ≤ 0.05 | 0.03 |
| Skept low for cold heading | ≤ 0.03 | 0.01 |
| Cr | 17 – 19 | 18 |
| Ni | 8 – 10 | 9 |
| Culowers work-hardening rate | 3 – 4 | 3.4 |
| Fe | balance |
What surface finishes work on 304Cu?
Passivate (nitric or citric) after forming, or electropolish for best appearance; mechanically polishes well to a bright finish, and no anodizing is applicable.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Organic Coating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 304Cu in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S30430-likeS30430
How much does 304Cu cost?
304Cu is a premium-cost stainless steel ($$$), cheaper than about 58% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
304Cu — frequently asked
What is 304Cu used for?
304Cu is typically used for cold-headed screws and bolts, drawn enclosures, cookware liners, stainless rivets, deep-drawn cups and shells and sink bowls. In short: cold-heading copper-bearing stainless.
What is the yield strength of 304Cu?
304Cu has a typical yield strength of 210 MPa (30.5 ksi) and a tensile strength of 500 MPa (72.5 ksi) — weaker than 100% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 304Cu easy to machine?
Not especially — machinability is rated fair (42/100, better than 79% of stainless steel grades). Gummy and work-hardening like 304 — use sharp, positive-rake carbide, heavy feed, rigid setup and flood coolant; avoid dwelling to prevent a hardened skin.
Can 304Cu be welded?
Yes — weldability is rated very good (72/100). Weldable by GTAW/GMAW/resistance methods with 308L filler; keep heat input low and avoid hot-crack-prone dilution because copper widens the solidification range.
What surface finishes work on 304Cu?
Passivate (nitric or citric) after forming, or electropolish for best appearance; mechanically polishes well to a bright finish, and no anodizing is applicable.
Can 304Cu be formed, bent or molded?
Excellent for multi-station cold heading, upsetting and deep drawing thanks to the low work-hardening rate; anneal between severe reductions and use chloride-free lubricants.
What is the maximum service temperature of 304Cu?
304Cu is rated for continuous use to about 750°C (1,382 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 304Cu cost?
304Cu is a premium-cost stainless steel ($$$), cheaper than about 58% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 304Cu?
Yes — 304Cu is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A493 — Stainless Steel Wire and Wire Rods for Cold Heading and Cold Forging — ASTM (2022)
- ASTM A314 / UNS S30430 (XM-7) chemistry — ASTM (2021)
- GB/T 1220 / 06Cr18Ni9Cu3 — SAC (2007)
- ISO 3506-1 Fasteners — Stainless steel, property class A2-70 — ISO (2020)
- ASM Handbook Vol.1 — Properties of Wrought Stainless Steels — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion of Stainless Steels — ASM International (2005)
- 302HQ / S30430 cold-heading wire datasheet — Sandvik / Suzuki Garphyttan (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.