Precious Metal AgC3 EXT-L
Heat-treated state · default condition
EXT-L = extruded, properties parallel to extrusion
Standard stocked form for contact rods/strip: highest density and conductivity, oriented graphite gives the lowest, most stable contact friction on the sliding face.
Values for the EXT-L condition
Other AgC3 tempers and conditions
AgC3 is listed in 4 conditions; see the grade overview at AgC3.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Extruded, properties transverse to extrusion direction | Same extruded stock evaluated across the graphite lamellae — use these lower numbers when current or heat must cross the alignment direction. | 90 | 120 | 4 | 38 HB | 64 % IACS |
Pressed, sintered, re-pressed and re-sintered | Choose when a pressed shape must reach near-full density and higher hardness/conductivity without extrusion. | 100 | 140 | 5 | 36 HB | 75 % IACS |
EXT-LDefaultThis page Extruded, properties parallel to extrusion | Standard stocked form for contact rods/strip: highest density and conductivity, oriented graphite gives the lowest, most stable contact friction on the sliding face. | 110 | 170 | 10 | 38 HB | 79 % IACS |
Pressed and sintered | Net-shape pressed tips/blocks with randomly oriented graphite: isotropic behaviour, slightly lower density, strength and conductivity than extruded. | — | 110 | 4 | 32 HB | 71 % IACS |
What is AgC3 EXT-L?
AgC3 EXT-L is AgC3 heat treated to EXT-L — standard stocked form for contact rods/strip: highest density and conductivity, oriented graphite gives the lowest, most stable contact friction on the sliding face. AgC3 EXT-L has a yield strength of 110 MPa (16 ksi) and a tensile strength of 170 MPa (24.7 ksi) — weaker than 80% of precious metal grades. Elongation at break is 10% and the elastic modulus is 62 GPa (8.99 Msi). AgC3 EXT-L has a density of 9.4 g/cm³ (0.34 lb/in³), lighter than 82% of precious metal grades. It melts at 961°C (1,762 °F).
Advantages
- Easy to machine — 62/100, better than 99% of precious metal grades
- High electrical conductivity — 79 % IACS, better than 81% of precious metal grades
- Conducts heat well — 320 W/m·K (184.9 BTU/hr·ft·°F), better than 80% of precious metal grades
Limitations
- Low stiffness — 62 GPa (8.99 Msi), worse than 99% of precious metal grades
- Hard to polish — 45/100, worse than 99% of precious metal grades
- Limited formability — 45/100, worse than 91% of precious metal grades
- Limited ductility — 10%, worse than 89% of precious metal grades
- Difficult to weld — 20/100, worse than 86% of precious metal grades
AgC3 EXT-L properties
Typical room-temperature values for AgC3 EXT-L; 12 are specific to this condition. Other listed values are AgC3 reference data and may not represent this condition. Bars are the position among precious metal grades.
Physical3
AgC3 EXT-L has a density of 9.4 g/cm³ (0.34 lb/in³), lighter than 82% of precious metal grades. It melts at 961°C (1,762 °F).
Mechanical11
AgC3 EXT-L has a yield strength of 110 MPa (16 ksi) and a tensile strength of 170 MPa (24.7 ksi) — weaker than 80% of precious metal grades. Elongation at break is 10% and the elastic modulus is 62 GPa (8.99 Msi).
Thermal6
AgC3 EXT-L is rated for continuous service to 250°C (482 °F). It conducts heat at 320 W/m·K (184.9 BTU/hr·ft·°F), better than 80% of precious metal grades. Thermal expansion is 19 µm/m·K (10.6 µin/in·°F).
Electrical3
AgC3 EXT-L conducts electricity at 79 % IACS, better than 81% of precious metal grades.
Chemical & Environmental3
Corrosion resistance is very good (75/100), worse than 61% of precious metal grades.
Sustainability4
Producing a kilogram of AgC3 EXT-L takes about 1,450 MJ of energy and emits 100 kg of CO₂ — less than 54% of precious metal grades. Typical recycled content is 40%.
Manufacturability6
AgC3 EXT-L's machinability is good (62/100, better than 99% of precious metal grades); weldability poor (20/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AgC3 EXT-L
Is AgC3 easy to machine?
Turns and drills easily with sharp, polished-flute carbide or HSS tools and light feeds; graphite dust is abrasive/conductive so collect it, and avoid smearing silver by using positive rake and no built-up-edge conditions.
Can AgC3 be welded?
Not fusion-weldable — graphite prevents sound fusion; attach by resistance welding or brazing only through a graphite-free fine-silver backing layer.
Can AgC3 be formed, bent or molded?
Supplied as pressed-sintered or extruded semi-finished product; cold coining, riveting and light bending are possible but ductility is low, so avoid tight-radius forming and cold heading of extruded stock across the grain.
What surface finishes work on AgC3?
Normally used as-machined or lightly ground; graphite pull-out limits mirror polish, and electroplating over the contact face is not done — clean with alcohol, avoid sulfur-bearing wraps and rubber packaging to prevent tarnish.
AgC3 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 |
|---|---|---|
| Cgraphite, ~12 vol%; lamellar or flake grade | 2.5 – 3.5 | 3 |
| Other (total impurities)Cu, Fe, Pb, O residuals | ≤ 0.15 | 0.05 |
| Agfine silver matrix, ≥99.95 % purity powder | ≥ 96.4 (balance) | — |
AgC3 EXT-L — frequently asked
What is AgC3 EXT-L used for?
AgC3 EXT-L is typically used for knife switches, disconnect blades and sliding contacts. In short: lowest-friction silver contact; strong anti-weld behaviour; low strength, low arc duty.
What is the yield strength of AgC3 EXT-L?
AgC3 EXT-L has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 170 MPa (24.7 ksi) — weaker than 80% of precious metal grades. Strength varies by condition: see the 4 listed tempers.
Is AgC3 EXT-L easy to machine?
Reasonably — machinability is rated good (62/100, better than 99% of precious metal grades). Turns and drills easily with sharp, polished-flute carbide or HSS tools and light feeds; graphite dust is abrasive/conductive so collect it, and avoid smearing silver by using positive rake and no built-up-edge conditions.
Can AgC3 EXT-L be welded?
Not readily — weldability is rated poor (20/100). Not fusion-weldable — graphite prevents sound fusion; attach by resistance welding or brazing only through a graphite-free fine-silver backing layer.
What surface finishes work on AgC3 EXT-L?
Normally used as-machined or lightly ground; graphite pull-out limits mirror polish, and electroplating over the contact face is not done — clean with alcohol, avoid sulfur-bearing wraps and rubber packaging to prevent tarnish.
Can AgC3 EXT-L be formed, bent or molded?
Supplied as pressed-sintered or extruded semi-finished product; cold coining, riveting and light bending are possible but ductility is low, so avoid tight-radius forming and cold heading of extruded stock across the grain.
What is the maximum service temperature of AgC3 EXT-L?
AgC3 EXT-L is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AgC3 EXT-L and AgC3 EXT-T?
EXT-L is the default condition — standard stocked form for contact rods/strip: highest density and conductivity, oriented graphite gives the lowest, most stable contact friction on the sliding face. EXT-T: same extruded stock evaluated across the graphite lamellae — use these lower numbers when current or heat must cross the alignment direction. Yield strength is 110 MPa in EXT-L versus 90 MPa in EXT-T.
Sources
- Data Book of Electrical Contacts (silver–graphite contact materials) — Doduco (2012)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Electrical Contact Materials) — ASM International (1990)
- Silver-graphite (AgC) contact material datasheets — Umicore / Metalor / (2023)
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.