Copper Alloy C18600
UNS C18600
C18600 is a chromium copper composition variant (also supplied against C18200) available in mill-hardened TM tempers, giving 510 MPa yield, 550 MPa tensile and 160 HB (83 HRB) at 78 % IACS and 300 W/m·K.
Reference datasheet — C18600 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the TM04 condition
C18600 tempers and conditions
C18600 is supplied in 11 conditions, soft to hard. TM04 is the default FabDigit quotes; the values on this page are for it.
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 |
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?
C18600 is a chromium copper composition variant (also supplied against C18200) available in mill-hardened TM tempers, giving 510 MPa yield, 550 MPa tensile and 160 HB (83 HRB) at 78 % IACS and 300 W/m·K. Strip and rod are used for welding electrodes, connectors and electrical contacts that need spring force plus current capacity without a customer-run heat treatment. Elongation is 8 %, service is limited to 350 °C, and a fusion weld loses 30–50 % of strength in the heat-affected zone; C18400 offers more ductility and C18100 more softening resistance above 350 °C. C18600 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). C18600 has a yield strength of 510 MPa (74 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 90% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 128 GPa (18.6 Msi).
What is C18600 used for?
- welding electrodes
- connectors
- electrical contacts
Advantages
- High service temperature — 350°C (662 °F), better than 95% of copper alloy grades
- High strength — 510 MPa (74 ksi), better than 90% of copper alloy grades
- Conducts heat well — 300 W/m·K (173.3 BTU/hr·ft·°F), better than 83% of copper alloy grades
- High electrical conductivity — 78 % IACS, better than 83% of copper alloy grades
Limitations
- Difficult to machine — 20/100, worse than 98% of copper alloy grades
- Limited ductility — 8%, worse than 83% of copper alloy grades
C18600 properties
Typical room-temperature values for C18600-TM04; bars are the position among copper alloy grades.
Physical3
C18600 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 has a yield strength of 510 MPa (74 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 90% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 128 GPa (18.6 Msi).
Thermal6
C18600 is rated for continuous service to 350°C (662 °F). It conducts heat at 300 W/m·K (173.3 BTU/hr·ft·°F), better than 83% of copper alloy grades. Thermal expansion is 17 µm/m·K (9.44 µin/in·°F).
Electrical3
C18600 conducts electricity at 78 % IACS, better than 83% 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 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's machinability is poor (20/100, worse than 98% of copper alloy grades); weldability fair (40/100); formability fair (40/100).
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 copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C18600 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C18600
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.
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 |
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.
Surface treatments FabDigit runs on copper alloy 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).
Equivalent designations
Standards and trade names that resolve to Copper Alloy C18600 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- C18200
How much does C18600 cost?
C18600 is a high-cost copper alloy ($$$$), pricier than about 78% 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.
C18600 — frequently asked
What is C18600 used for?
C18600 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?
C18600 has a typical yield strength of 510 MPa (74 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 90% of copper alloy grades. Strength varies by condition: see the 11 listed tempers.
Is C18600 easy to machine?
Not especially — machinability is rated poor (20/100, worse than 98% 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 be welded?
With care — weldability is rated fair (40/100). 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?
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 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?
C18600 is rated for continuous use to about 350°C (662 °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.
How much does C18600 cost?
C18600 is a high-cost copper alloy ($$$$), pricier than about 78% 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.
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; 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.