Copper Alloy M2r
Grade
M2r = м2р
Choose when the part must be welded or brazed in reducing atmosphere — residual P removes oxygen and prevents hydrogen embrittlement, at the cost of conductivity.
Values for the M2r condition
Other M2 tempers and conditions
M2 is listed in 4 conditions; see the grade overview at M2.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
MDefault Thermomechanically controlled processed | Pick for deep drawing, bending, gaskets and flexible conductors where maximum ductility and conductivity matter. | 70 | 220 | 45 | 45 HB | 97 % IACS |
M2rThis page М2р | Choose when the part must be welded or brazed in reducing atmosphere — residual P removes oxygen and prevents hydrogen embrittlement, at the cost of conductivity. | 70 | 220 | 42 | 45 HB | 85 % IACS |
М2П | Compromise temper for busbars, terminals and stamped parts that need some stiffness but still moderate bending ability. | 240 | 300 | 14 | 85 HB | 96 % IACS |
М2Т | Pick for hard-drawn wire, rods, rigid busbars and contact parts needing highest strength and straightness. | 320 | 370 | 6 | 100 HB | 95 % IACS |
What is M2r?
M2r is M2 in the M2r grade — choose when the part must be welded or brazed in reducing atmosphere — residual P removes oxygen and prevents hydrogen embrittlement, at the cost of conductivity. M2r has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 93% of copper alloy grades. Elongation at break is 42% and the elastic modulus is 115 GPa (16.7 Msi). M2r has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,065°C (1,949 °F). M is the default condition FabDigit quotes; M2r is available on request or by drawing note.
Advantages
- Forms and bends easily — 92/100, better than 91% of copper alloy grades
- Tough — resists crack growth — 60 MPa·√m (54.6 ksi·√in), better than 90% of copper alloy grades
- Readily welded — 75/100, better than 89% of copper alloy grades
- Ductile — tolerates forming and impact — 42%, better than 86% of copper alloy grades
- Conducts heat well — 340 W/m·K (196.4 BTU/hr·ft·°F), better than 86% of copper alloy grades
Limitations
- Low strength — 70 MPa (10.2 ksi), worse than 93% of copper alloy grades
M2r properties
Typical room-temperature values for M2r; 20 are specific to this condition. Other listed values are M2 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
M2r has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,065°C (1,949 °F).
Mechanical14
M2r has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 93% of copper alloy grades. Elongation at break is 42% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
M2r is rated for continuous service to 250°C (482 °F). It conducts heat at 340 W/m·K (196.4 BTU/hr·ft·°F), better than 86% of copper alloy grades. Thermal expansion is 17 µm/m·K (9.44 µin/in·°F).
Electrical3
M2r conducts electricity at 85 % IACS, better than 86% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of M2r takes about 57 MJ of energy and emits 3.8 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 35%.
Manufacturability8
M2r's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability very good (75/100); formability excellent (92/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with M2r
Is M2 easy to machine?
Gummy and long-chipping — use sharp positive-rake tools, high speed, low feed and generous coolant; expect ~20 % of AISI 1212 rate, prefer free-cutting brass if heavy machining is needed.
Can M2 be welded?
Oxygen-bearing copper is prone to hydrogen embrittlement and porosity — braze/solder or use GTAW/GMAW with high preheat and deoxidized filler (or specify М2р) rather than gas welding in reducing atmosphere.
Can M2 be formed, bent or molded?
Excellent cold formability in the soft temper (deep drawing, bending, riveting); interanneal at 450–600 °C when total cold reduction exceeds ~60 %.
What surface finishes work on M2?
Not anodizable; polishes to a bright finish but tarnishes quickly — protect with benzotriazole lacquer, tin/nickel/silver plating, or allow natural patina outdoors.
M2 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 |
|---|---|---|
| Ooxygen-bearing (tough pitch) grade | ≤ 0.07 | 0.04 |
| Bi | ≤ 0 | — |
| Sb | ≤ 0.01 | — |
| As | ≤ 0.01 | — |
| Fe | ≤ 0.05 | — |
| Ni | ≤ 0.2 | — |
| Pb | ≤ 0.01 | — |
| Sn | ≤ 0.05 | — |
| Zn | ≤ 0.04 | — |
| S | ≤ 0.01 | — |
| Pup to ~0.04 residual P in the М2р deoxidized variant | ≤ 0.01 | — |
| Total impurities | ≤ 0.3 | — |
| CuCu + Ag combined, per GOST 859 | ≥ 99.7 (balance) | — |
M2r — frequently asked
What is M2r used for?
M2r is typically used for general fittings, roofing and flashing and non-critical electrical parts. In short: commercial-grade CIS copper; lower purity than M1; non-critical electrical use.
What is the yield strength of M2r?
M2r has a typical yield strength of 70 MPa (10.2 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 93% of copper alloy grades. Strength varies by condition: see the 4 listed tempers.
Is M2r easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Gummy and long-chipping — use sharp positive-rake tools, high speed, low feed and generous coolant; expect ~20 % of AISI 1212 rate, prefer free-cutting brass if heavy machining is needed.
Can M2r be welded?
Yes — weldability is rated very good (75/100). Oxygen-bearing copper is prone to hydrogen embrittlement and porosity — braze/solder or use GTAW/GMAW with high preheat and deoxidized filler (or specify М2р) rather than gas welding in reducing atmosphere.
What surface finishes work on M2r?
Not anodizable; polishes to a bright finish but tarnishes quickly — protect with benzotriazole lacquer, tin/nickel/silver plating, or allow natural patina outdoors.
Can M2r be formed, bent or molded?
Excellent cold formability in the soft temper (deep drawing, bending, riveting); interanneal at 450–600 °C when total cold reduction exceeds ~60 %.
What is the maximum service temperature of M2r?
M2r 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 M2-M and M2-T?
M is the default condition — pick for deep drawing, bending, gaskets and flexible conductors where maximum ductility and conductivity matter. T: pick for hard-drawn wire, rods, rigid busbars and contact parts needing highest strength and straightness. Yield strength is 70 MPa in M versus 320 MPa in T.
Sources
- GOST 859-2014 Copper. Grades (М00, М1, М2, М3, М2р…) — Rosstandart (2014)
- GOST 1173 / GOST 495 — copper sheet, strip and foil (tempers М, П, Т) — Rosstandart (2006)
- C11000 Electrolytic Tough Pitch Copper alloy datasheet — Copper Development Association (copper.org) (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.