Copper Alloy C18600-H04
Supply condition
UNS C18600
H04 = full hard
Maximum cold-worked strength before ageing; used where a subsequent age hardening step follows.
Values for the H04 condition
Other C18600 tempers and conditions
C18600 is listed in 11 conditions; see the grade overview at C18600.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution heat treated | Choose for deep forming, heavy machining or fabrication before a customer ageing cycle. | 95 | 250 | 40 | 60 HB | 42 % IACS |
Half hard | Cold-rolled strip for parts that will be formed then precipitation aged in-house. | 300 | 360 | 12 | 105 HB | 45 % IACS |
Mill hardened | Mill-hardened strip for connector contacts requiring very tight bend radii. | 350 | 420 | 18 | 118 HB | 82 % IACS |
H04This page Full hard | Maximum cold-worked strength before ageing; used where a subsequent age hardening step follows. | 380 | 420 | 6 | 125 HB | 45 % IACS |
TD02 and precipitation hardened | Rod/bar temper giving a good balance of conductivity and moderate strength for electrodes and machined contacts. | 390 | 460 | 18 | 140 HB | 80 % IACS |
Mill hardened, low strength level | Intermediate mill-hardened level when TM00 lacks contact force but TM02 will not form. | 390 | 450 | 15 | 133 HB | 80 % IACS |
Mill hardened, half hard | Most-formable of the high-force connector tempers: pick when 90° bends with small radii are needed at ~500 MPa strength. | 450 | 500 | 12 | 148 HB | 80 % IACS |
TD04 and precipitation hardened | Standard rod/bar condition for resistance-welding electrodes and high-load current-carrying parts. | 460 | 520 | 14 | 155 HB | 78 % IACS |
TM04Default Mill hardened, full hard | Default stocked connector-strip temper: highest contact force and stress relaxation resistance still compatible with moderate forming. | 510 | 550 | 8 | 160 HB | 78 % IACS |
Mill hardened, extra hard | For flat springs and contacts needing maximum force where bends are gentle or along the good bend direction. | 560 | 590 | 6 | 10 HRC | 76 % IACS |
Mill hardened, spring hard | Top mill-hardened strength for miniature high-force contacts; bending capability is marginal. | 600 | 630 | 4 | 13 HRC | 74 % IACS |
What is C18600-H04?
C18600-H04 is C18600 supplied in the H04 condition — maximum cold-worked strength before ageing; used where a subsequent age hardening step follows. C18600-H04 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 420 MPa (60.9 ksi) — stronger than 77% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 128 GPa (18.6 Msi). C18600-H04 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,070°C (1,958 °F). TM04 is the default condition FabDigit quotes; H04 is available on request or by drawing note.
Advantages
- High strength — 380 MPa (55.1 ksi), better than 77% of copper alloy grades
- High electrical conductivity — 45 % IACS, better than 77% of copper alloy grades
- Conducts heat well — 180 W/m·K (104 BTU/hr·ft·°F), better than 75% of copper alloy grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 96% of copper alloy grades
- Limited ductility — 6%, worse than 89% of copper alloy grades
- Difficult to machine — 25/100, worse than 86% of copper alloy grades
C18600-H04 properties
Typical room-temperature values for C18600-H04; 20 are specific to this condition. Other listed values are C18600 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C18600-H04 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,070°C (1,958 °F).
Mechanical13
C18600-H04 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 420 MPa (60.9 ksi) — stronger than 77% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 128 GPa (18.6 Msi).
Thermal6
C18600-H04 is rated for continuous service to 150°C (302 °F). It conducts heat at 180 W/m·K (104 BTU/hr·ft·°F), better than 75% of copper alloy grades. Thermal expansion is 17 µm/m·K (9.44 µin/in·°F).
Electrical3
C18600-H04 conducts electricity at 45 % IACS, better than 77% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C18600-H04 takes about 57 MJ of energy and emits 3.6 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 35%.
Manufacturability7
C18600-H04's machinability is poor (25/100, worse than 86% of copper alloy grades); weldability fair (38/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C18600-H04
Is C18600 easy to machine?
Gummy and abrasive-free: use sharp positive-rake carbide, high speed, light-to-moderate feed and flood coolant; rating about 20 % of free-cutting brass, chip breaking is the main problem.
Can C18600 be welded?
Resistance and electron-beam/laser welding work best; GTAW is possible with Cu-Cr or Cu-Si filler but the HAZ over-ages and loses 30–50 % of strength — re-age if properties matter.
Can C18600 be formed, bent or molded?
Form in TB00/H02 for deep draws; mill-hardened TM02 bends to roughly 1–2 t good-way while TM04 and above need larger radii and bad-way bends should be avoided.
What surface finishes work on C18600?
Not anodisable — barrel or reel-to-reel plate with Ni underlayer plus Sn, Ag or Au for contacts; chromium-bearing oxide needs an activating acid dip before plating and a benzotriazole rinse prevents tarnish on bare parts.
C18600 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 |
|---|---|---|
| Crprincipal precipitation-hardening element of the C186xx chromium copper family | 0.4 – 1.2 | 0.8 |
| Feimpurity limit | ≤ 0.1 | 0.03 |
| Siimpurity/deoxidiser residual | ≤ 0.1 | 0.03 |
| CuCu + named elements ≥ 99.5 %; verify exact registered limits against the current CDA/UNS registration and ASTM B888 for connector strip | balance | — |
C18600-H04 — frequently asked
What is C18600-H04 used for?
C18600-H04 is typically used for welding electrodes, connectors and electrical contacts. In short: mill-hardened chromium copper; 78 % IACS at 510 MPa; no heat treatment needed.
What is the yield strength of C18600-H04?
C18600-H04 has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 420 MPa (60.9 ksi) — stronger than 77% of copper alloy grades. Strength varies by condition: see the 11 listed tempers.
Is C18600-H04 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 86% of copper alloy grades). Gummy and abrasive-free: use sharp positive-rake carbide, high speed, light-to-moderate feed and flood coolant; rating about 20 % of free-cutting brass, chip breaking is the main problem.
Can C18600-H04 be welded?
With care — weldability is rated fair (38/100). Resistance and electron-beam/laser welding work best; GTAW is possible with Cu-Cr or Cu-Si filler but the HAZ over-ages and loses 30–50 % of strength — re-age if properties matter.
What surface finishes work on C18600-H04?
Not anodisable — barrel or reel-to-reel plate with Ni underlayer plus Sn, Ag or Au for contacts; chromium-bearing oxide needs an activating acid dip before plating and a benzotriazole rinse prevents tarnish on bare parts.
Can C18600-H04 be formed, bent or molded?
Form in TB00/H02 for deep draws; mill-hardened TM02 bends to roughly 1–2 t good-way while TM04 and above need larger radii and bad-way bends should be avoided.
What is the maximum service temperature of C18600-H04?
C18600-H04 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C18600-TM04 and C18600-TB00?
TM04 is the default condition — default stocked connector-strip temper: highest contact force and stress relaxation resistance still compatible with moderate forming. TB00: choose for deep forming, heavy machining or fabrication before a customer ageing cycle. Yield strength is 510 MPa in TM04 versus 95 MPa in TB00.
Sources
- ASTM B888/B888M — Copper Alloy Strip for Use in Manufacture of Electrical Connectors or Spring Contacts — ASTM International (2020)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM International (2019)
- ASTM B224 — Classification of Coppers — ASTM International (2021)
- CDA/UNS Copper Alloy Property Datasheets (C182xx–C186xx chromium coppers) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
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.