Copper Alloy C36700-M20
Finish state · default condition
UNS C36700 · ASTM B121
M20 = as hot rolled
Standard condition for ASTM B171 condenser tube sheets and heavy plate; best combination of strength and machinability.
Values for the M20 condition
Other C36700 tempers and conditions
C36700 is listed in 6 conditions; see the grade overview at C36700.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Use when maximum ductility for bending, expanding or rolling-in of tubes is needed. | 125 | 360 | 50 | 90 HB | 28 % IACS |
As hot extruded | Pick for extruded bar, architectural shapes and forging stock where machining follows. | 140 | 370 | 48 | 100 HB | 28 % IACS |
As hot forged and air cooled | Condition of hot-forged valve bodies and hardware bodies straight off the press. | 140 | 370 | 45 | 100 HB | 28 % IACS |
M20DefaultThis page As hot rolled | Standard condition for ASTM B171 condenser tube sheets and heavy plate; best combination of strength and machinability. | 145 | 380 | 45 | 105 HB | 28 % IACS |
Quarter hard | Light cold work for higher yield strength in flat products while keeping some bendability. | 275 | 425 | 25 | 125 HB | 27 % IACS |
Half hard | Choose for straight, stiff bar and strip needing the highest strength available in this alloy. | 345 | 470 | 18 | 145 HB | 27 % IACS |
What is C36700-M20?
C36700-M20 is C36700 supplied in the M20 condition — standard condition for ASTM B171 condenser tube sheets and heavy plate; best combination of strength and machinability. C36700-M20 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 72% of copper alloy grades. Elongation at break is 45% and the elastic modulus is 103 GPa (14.9 Msi). C36700-M20 has a density of 8.41 g/cm³ (0.304 lb/in³), lighter than 72% of copper alloy grades. It melts at 885°C (1,625 °F).
Advantages
- Ductile — tolerates forming and impact — 45%, better than 91% of copper alloy grades
Limitations
- Needs corrosion protection — 48/100, worse than 96% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C36700-M20 properties
Typical room-temperature values for C36700-M20; 21 are specific to this condition. Other listed values are C36700 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C36700-M20 has a density of 8.41 g/cm³ (0.304 lb/in³), lighter than 72% of copper alloy grades. It melts at 885°C (1,625 °F).
Mechanical15
C36700-M20 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 72% of copper alloy grades. Elongation at break is 45% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C36700-M20 is rated for continuous service to 200°C (392 °F). It conducts heat at 123 W/m·K (71.1 BTU/hr·ft·°F), better than 70% of copper alloy grades. Thermal expansion is 20.8 µm/m·K (11.6 µin/in·°F).
Electrical3
C36700-M20 conducts electricity at 28 % IACS, better than 69% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 96% of copper alloy grades.
Sustainability4
Producing a kilogram of C36700-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 70%.
Manufacturability7
C36700-M20's machinability is good (60/100, better than 74% of copper alloy grades); weldability poor (25/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C36700-M20
Is C36700 easy to machine?
Free-cutting at ~60 % of C36000 — use sharp, high-rake carbide or HSS tools, light feeds and flood coolant; chips break well thanks to the lead.
Can C36700 be welded?
Arc and gas welding are not recommended (lead cracking, zinc fume); join by soft soldering or silver brazing with good ventilation.
Can C36700 be formed, bent or molded?
Excellent hot working at 620–760 °C (forging, extrusion, hot rolling); cold formability is limited by the β phase — anneal at 425–600 °C between severe operations.
What surface finishes work on C36700?
Takes a bright mechanical polish and standard brass lacquer, chromate or Ni/Cr plating; stress-relieve at ~275 °C before service in ammonia-bearing atmospheres.
C36700 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 when reported | 58 – 61 | 59.5 |
| Pbfree-machining addition | 0.25 – 0.7 | 0.5 |
| Fe | ≤ 0.15 | 0.05 |
| Sbdezincification inhibitor (antimonial grade) | 0.02 – 0.1 | 0.05 |
| Zn≈ 39–41 % | balance | — |
C36700-M20 — frequently asked
What is C36700-M20 used for?
C36700-M20 is typically used for architectural fittings, valve components and decorative extrusions. In short: mid-lead Muntz metal; free-cutting 60/40 brass; good hot forging alloy.
What is the yield strength of C36700-M20?
C36700-M20 has a typical yield strength of 145 MPa (21 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 72% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is C36700-M20 easy to machine?
Reasonably — machinability is rated good (60/100, better than 74% of copper alloy grades). Free-cutting at ~60 % of C36000 — use sharp, high-rake carbide or HSS tools, light feeds and flood coolant; chips break well thanks to the lead.
Can C36700-M20 be welded?
Not readily — weldability is rated poor (25/100). Arc and gas welding are not recommended (lead cracking, zinc fume); join by soft soldering or silver brazing with good ventilation.
What surface finishes work on C36700-M20?
Takes a bright mechanical polish and standard brass lacquer, chromate or Ni/Cr plating; stress-relieve at ~275 °C before service in ammonia-bearing atmospheres.
Can C36700-M20 be formed, bent or molded?
Excellent hot working at 620–760 °C (forging, extrusion, hot rolling); cold formability is limited by the β phase — anneal at 425–600 °C between severe operations.
What is the maximum service temperature of C36700-M20?
C36700-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 C36700-M20 and C36700-H02?
M20 is the default condition — standard condition for ASTM B171 condenser tube sheets and heavy plate; best combination of strength and machinability. H02: choose for straight, stiff bar and strip needing the highest strength available in this alloy. Yield strength is 145 MPa in M20 versus 345 MPa in H02.
Sources
- ASTM B171/B171M — Copper-Alloy Plate and Sheet for Pressure Vessels, Condensers and Heat Exchangers — ASTM International (2018)
- ASTM B121/B121M — Leaded Brass Plate, Sheet, Strip and Rolled Bar — ASTM International (2020)
- CDA Alloy Database, C36500–C36800 leaded Muntz metal — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (copper alloys) — ASM International (2005)
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.