Copper Alloy C17460-TM08
Precip hard
UNS C17460 · ASTM B441
TM08 = mill hardened, spring hard
Highest mill-hardened strength for flat springs and minimal-deflection contacts; limited forming.
Values for the TM08 condition
Other C17460 tempers and conditions
C17460 is listed in 8 conditions; see the grade overview at C17460.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution heat treated | Softest condition for deep forming, stamping or machining before customer age hardening. | 170 | 340 | 28 | 95 HB | 28 % IACS |
Solution heat treated and cold worked, full hard | Cold-drawn/rolled but not aged; chosen when the part is formed then age hardened to HT. | 450 | 520 | 10 | 145 HB | 30 % IACS |
Mill hardened, half hard | Mill-hardened strip for formed contacts needing good bend ductility with no customer heat treatment. | 550 | 660 | 14 | 185 HB | 52 % IACS |
TF00Default Solution heat treated and precipitation hardened | Standard stocked rod/bar condition: peak-aged for balanced 700–830 MPa strength with ~50% IACS conductivity. | 620 | 760 | 12 | 95 HRB | 52 % IACS |
Mill hardened, full hard | Mid-range mill-hardened strip temper balancing forming and spring force. | 620 | 730 | 11 | 18 HRC | 52 % IACS |
Mill hardened, extra hard | Common connector strip temper: high contact force with moderate bendability transverse to rolling. | 710 | 800 | 9 | 22 HRC | 50 % IACS |
TD04 and precipitation hardened | Highest strength condition for springs and heavily loaded contacts where ductility can be low. | 740 | 830 | 8 | 25 HRC | 50 % IACS |
TM08This page Mill hardened, spring hard | Highest mill-hardened strength for flat springs and minimal-deflection contacts; limited forming. | 780 | 860 | 7 | 24 HRC | 50 % IACS |
What is C17460-TM08?
C17460-TM08 is C17460 in the TM08 condition — highest mill-hardened strength for flat springs and minimal-deflection contacts; limited forming. C17460-TM08 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 98% of copper alloy grades. Elongation at break is 7% and the elastic modulus is 138 GPa (20 Msi). C17460-TM08 has a density of 8.83 g/cm³ (0.319 lb/in³), heavier than 65% of copper alloy grades. It melts at 1,000°C (1,832 °F). TF00 is the default condition FabDigit quotes; TM08 is available on request or by drawing note.
Advantages
- High strength — 780 MPa (113 ksi), better than 98% of copper alloy grades
- Stiff — 138 GPa (20 Msi), better than 95% of copper alloy grades
- High service temperature — 320°C (608 °F), better than 93% of copper alloy grades
- Conducts heat well — 220 W/m·K (127.1 BTU/hr·ft·°F), better than 80% of copper alloy grades
- High electrical conductivity — 50 % IACS, better than 79% of copper alloy grades
Limitations
- High embodied carbon — 6.5 kg CO₂/kg, worse than 94% of copper alloy grades
- Limited ductility — 7%, worse than 86% of copper alloy grades
C17460-TM08 properties
Typical room-temperature values for C17460-TM08; 23 are specific to this condition. Other listed values are C17460 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C17460-TM08 has a density of 8.83 g/cm³ (0.319 lb/in³), heavier than 65% of copper alloy grades. It melts at 1,000°C (1,832 °F).
Mechanical13
C17460-TM08 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 98% of copper alloy grades. Elongation at break is 7% and the elastic modulus is 138 GPa (20 Msi).
Thermal6
C17460-TM08 is rated for continuous service to 320°C (608 °F). It conducts heat at 220 W/m·K (127.1 BTU/hr·ft·°F), better than 80% of copper alloy grades. Thermal expansion is 17.5 µm/m·K (9.72 µin/in·°F).
Electrical3
C17460-TM08 conducts electricity at 50 % IACS, better than 79% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 58% of copper alloy grades.
Sustainability4
Producing a kilogram of C17460-TM08 takes about 95 MJ of energy and emits 6.5 kg of CO₂ — more than 95% of copper alloy grades. Typical recycled content is 30%.
Manufacturability8
C17460-TM08's machinability is fair (48/100, better than 68% of copper alloy grades); weldability fair (40/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C17460-TM08
Is C17460 easy to machine?
Machines like a hard bronze — carbide tooling, positive rake, flood coolant; wet-cut and capture fines/dust because of beryllium content (OSHA/ACGIH exposure controls).
Can C17460 be welded?
Resistance and electron-beam welding good; GTAW possible with matching filler but the heat-affected zone loses age-hardened strength and normally needs re-solutioning and re-aging.
Can C17460 be formed, bent or molded?
Form in TB00/TD04 then age (600–800 °F class cycle, roughly 3 h at ~480 °C) for peak properties; mill-hardened TM tempers are formed as delivered with grain-direction bend limits.
What surface finishes work on C17460?
Not anodizable; electroplate Ni barrier plus Sn, Ag or Au for contacts, or passivate/lacquer to limit tarnish; polishes to a bright finish.
C17460 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 |
|---|---|---|
| Beberyllium provides precipitation hardening | 0.15 – 0.5 | 0.3 |
| Ni | 1 – 1.4 | 1.2 |
| Curemainder; named impurities limited per ASTM B441/B534 | balance | — |
C17460-TM08 — frequently asked
What is C17460-TM08 used for?
C17460-TM08 is typically used for connector springs, electronic contacts and relay components. In short: highest service temp in group; low-cobalt connector alloy; limited cold formability.
What is the yield strength of C17460-TM08?
C17460-TM08 has a typical yield strength of 780 MPa (113 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 98% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C17460-TM08 easy to machine?
Reasonably — machinability is rated fair (48/100, better than 68% of copper alloy grades). Machines like a hard bronze — carbide tooling, positive rake, flood coolant; wet-cut and capture fines/dust because of beryllium content (OSHA/ACGIH exposure controls).
Can C17460-TM08 be welded?
With care — weldability is rated fair (40/100). Resistance and electron-beam welding good; GTAW possible with matching filler but the heat-affected zone loses age-hardened strength and normally needs re-solutioning and re-aging.
What surface finishes work on C17460-TM08?
Not anodizable; electroplate Ni barrier plus Sn, Ag or Au for contacts, or passivate/lacquer to limit tarnish; polishes to a bright finish.
Can C17460-TM08 be formed, bent or molded?
Form in TB00/TD04 then age (600–800 °F class cycle, roughly 3 h at ~480 °C) for peak properties; mill-hardened TM tempers are formed as delivered with grain-direction bend limits.
What is the maximum service temperature of C17460-TM08?
C17460-TM08 is rated for continuous use to about 320°C (608 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C17460-TF00 and C17460-TB00?
TF00 is the default condition — standard stocked rod/bar condition: peak-aged for balanced 700–830 MPa strength with ~50% IACS conductivity. TB00: softest condition for deep forming, stamping or machining before customer age hardening. Yield strength is 620 MPa in TF00 versus 170 MPa in TB00.
Sources
- ASTM B441 — Copper-Cobalt-Beryllium and Copper-Nickel-Beryllium Rod and Bar — ASTM International (2021)
- ASTM B534 — Copper-Cobalt-Beryllium / Copper-Nickel-Beryllium Plate, Sheet, Strip and Rolled Bar — ASTM International (2018)
- Alloy 174 (C17460) high-conductivity beryllium copper data — Materion Brush Performance Alloys (2021)
- UNS C17460 alloy datasheet — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — 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.