Copper Alloy C69400-M20
Finish state
UNS C69400 · ASTM B371
M20 = as hot rolled
Condition of net-shape hot-forged valve stems and fittings before machining; properties close to as-extruded.
Values for the M20 condition
Other C69400 tempers and conditions
C69400 is listed in 6 conditions; see the grade overview at C69400.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Pick when maximum ductility for cold heading, bending or spinning is needed before final sizing. | 205 | 480 | 35 | 115 HB | 7 % IACS |
M20This page As hot rolled | Condition of net-shape hot-forged valve stems and fittings before machining; properties close to as-extruded. | 310 | 590 | 25 | 155 HB | 6.7 % IACS |
M30Default As hot extruded | Standard stock condition for silicon red brass rod, bar and shapes per ASTM B371 — best balance of strength and ductility. | 345 | 620 | 25 | 165 HB | 6.7 % IACS |
Half hard | Cold-drawn rod for better straightness, tighter tolerance and higher yield strength with useful residual ductility. | 415 | 655 | 20 | 180 HB | 6.6 % IACS |
Drawn and stress relieved | Drawn rod given a low-temperature stress relief to cut residual stress and SCC risk while keeping most cold-work strength. | 430 | 660 | 18 | 183 HB | 6.5 % IACS |
Full hard | Highest-strength drawn condition for valve stems and threaded parts where wear and thread strength govern. | 470 | 700 | 15 | 195 HB | 6.5 % IACS |
What is C69400-M20?
C69400-M20 is C69400 supplied in the M20 condition — condition of net-shape hot-forged valve stems and fittings before machining; properties close to as-extruded. C69400-M20 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 64% of copper alloy grades. Elongation at break is 25% and the elastic modulus is 103 GPa (14.9 Msi). C69400-M20 has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 820°C (1,508 °F). M30 is the default condition FabDigit quotes; M20 is available on request or by drawing note.
Limitations
- Poor heat conductor — 28.5 W/m·K (16.5 BTU/hr·ft·°F), worse than 95% of copper alloy grades
- Low electrical conductivity — 6.7 % IACS, worse than 89% of copper alloy grades
C69400-M20 properties
Typical room-temperature values for C69400-M20; 20 are specific to this condition. Other listed values are C69400 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C69400-M20 has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 820°C (1,508 °F).
Mechanical12
C69400-M20 has a yield strength of 310 MPa (45 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 64% of copper alloy grades. Elongation at break is 25% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C69400-M20 is rated for continuous service to 200°C (392 °F). It conducts heat at 28.5 W/m·K (16.5 BTU/hr·ft·°F), worse than 95% of copper alloy grades. Thermal expansion is 20.2 µm/m·K (11.2 µin/in·°F).
Electrical3
C69400-M20 conducts electricity at 6.7 % IACS, worse than 89% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 64% of copper alloy grades.
Sustainability4
Producing a kilogram of C69400-M20 takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 40%.
Manufacturability8
C69400-M20's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability fair (45/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C69400-M20
Is C69400 easy to machine?
Machinability ≈30% of C36000 — use sharp positive-rake carbide, high speed with generous coolant; chips are stringy, so chipbreakers and reduced feeds are needed versus leaded brass.
Can C69400 be welded?
Solders and brazes readily; GTAW/GMAW with silicon-bronze filler is acceptable, but oxyacetylene welding is not recommended because of zinc/silicon loss.
Can C69400 be formed, bent or molded?
Excellent hot extrudability and hot forgeability at ~700–800 °C; cold formability only fair, so limit cold reductions and anneal between heavy operations.
What surface finishes work on C69400?
Polishes to a bright golden finish; accepts nickel/chrome plating well — passivate with benzotriazole or lacquer to avoid tarnish, no anodizing.
C69400 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 |
|---|---|---|
| Cuincludes Ag | 80 – 83 | 81.5 |
| Si | 3.5 – 4.5 | 4 |
| Pblow-lead / lead-free plumbing grades often ≤0.09 | ≤ 0.3 | 0.05 |
| Fe | ≤ 0.2 | 0.05 |
| Znremainder, ~12–16% | balance | — |
C69400-M20 — frequently asked
What is C69400-M20 used for?
C69400-M20 is typically used for plumbing tube, fittings and lead-free water system components. In short: lead-free plumbing brass; high-strength silicon brass; hot-forged, not free-cutting.
What is the yield strength of C69400-M20?
C69400-M20 has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 590 MPa (85.6 ksi) — stronger than 64% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is C69400-M20 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Machinability ≈30% of C36000 — use sharp positive-rake carbide, high speed with generous coolant; chips are stringy, so chipbreakers and reduced feeds are needed versus leaded brass.
Can C69400-M20 be welded?
With care — weldability is rated fair (45/100). Solders and brazes readily; GTAW/GMAW with silicon-bronze filler is acceptable, but oxyacetylene welding is not recommended because of zinc/silicon loss.
What surface finishes work on C69400-M20?
Polishes to a bright golden finish; accepts nickel/chrome plating well — passivate with benzotriazole or lacquer to avoid tarnish, no anodizing.
Can C69400-M20 be formed, bent or molded?
Excellent hot extrudability and hot forgeability at ~700–800 °C; cold formability only fair, so limit cold reductions and anneal between heavy operations.
What is the maximum service temperature of C69400-M20?
C69400-M20 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C69400-M30 and C69400-O60?
M30 is the default condition — standard stock condition for silicon red brass rod, bar and shapes per ASTM B371 — best balance of strength and ductility. O60: pick when maximum ductility for cold heading, bending or spinning is needed before final sizing. Yield strength is 345 MPa in M30 versus 205 MPa in O60.
Sources
- ASTM B371/B371M — Copper-Zinc-Silicon Alloy Rod — ASTM International (2019)
- CDA Alloy Datasheet C69400 (Silicon Red Brass) — Copper Development Association (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.