Stainless Steel 304Cu · supply condition
Stainless Steel 304Cu-1/4 Hard
Properties of the 1/4 Hard condition, compared with the other 304Cu tempers.
Use when a modest strength increase is needed but the part still has to be bent or roll-formed.
What is 304Cu-1/4 Hard?
304Cu-1/4 Hard is 304Cu supplied in the 1/4 Hard condition — use when a modest strength increase is needed but the part still has to be bent or roll-formed. 304Cu-1/4 Hard has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 83% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 193 GPa (28 Msi). 304Cu-1/4 Hard has a density of 7.93 g/cm³ (0.286 lb/in³), heavier than 76% of stainless steel grades. It melts at 1,400°C (2,552 °F). Annealed is the default condition FabDigit quotes; 1/4 Hard is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 82/100, better than 95% of stainless steel grades
- High strength — 550 MPa (79.8 ksi), better than 83% of stainless steel grades
Limitations
- Limited ductility — 12%, worse than 95% of stainless steel grades
304Cu-1/4 Hard properties
Typical room-temperature values for 304Cu-1/4 Hard — 8 properties are specific to this condition; the rest are grade-level values shared by every 304Cu temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
304Cu-1/4 Hard has a density of 7.93 g/cm³ (0.286 lb/in³), heavier than 76% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical14
304Cu-1/4 Hard has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 83% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
304Cu-1/4 Hard 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-1/4 Hard conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 53% of stainless steel grades.
Sustainability4
Producing a kilogram of 304Cu-1/4 Hard takes about 55 MJ of energy and emits 4.5 kg of CO₂ — less than 51% of stainless steel grades. Typical recycled content is 65%.
Manufacturability7
304Cu-1/4 Hard's machinability is fair (42/100, better than 79% of stainless steel grades); weldability very good (72/100); formability good (55/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 304Cu tempers and conditions
304Cu is also supplied in 4 other conditions. The full side-by-side table is on the 304Cu overview.
- AnnealedDefaultDefault stock condition for cold heading, riveting and deep drawing where maximum ductility is needed.210 MPa yield · 145 HB
- 1/4 HardUse when a modest strength increase is needed but the part still has to be bent or roll-formed.550 MPa yield · 25 HRC
- Cold DrawnPick for wire and bar that must hold size and give higher strength while still allowing moderate forming or threading.520 MPa yield · 20 HRC
Working with 304Cu-1/4 Hard
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.
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.
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 | — |
304Cu-1/4 Hard — frequently asked
What is 304Cu-1/4 Hard used for?
304Cu-1/4 Hard 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-1/4 Hard?
304Cu-1/4 Hard has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 83% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 304Cu-1/4 Hard 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-1/4 Hard 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-1/4 Hard?
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-1/4 Hard 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-1/4 Hard?
304Cu-1/4 Hard 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.
Can FabDigit make parts in 304Cu-1/4 Hard?
Yes — 304Cu-1/4 Hard is available for CNC machining and sheet metal with instant online pricing. 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.