Copper Alloy C72150-HR (Hot rolled)
Supply condition
UNS C72150 · EN CuNi44Mn1 · GB BMn40-1.5
Pick for precision resistors, shunts and load cells: a 250–400 °C stabilizing bake locks in resistance and minimizes long-term drift.
Values for the HR condition
Other C72150 tempers and conditions
C72150 is listed in 9 conditions; see the grade overview at C72150.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
O60Default Soft annealed | Standard stocked condition for resistance wire, shunt strip and thermocouple wire — maximum ductility and the most stable, lowest-drift resistivity. | 200 | 460 | 38 | 90 HB | 3.5 % IACS |
Annealed | Use where a defined grain size is needed for deep drawing or fine-foil rolling of strain-gauge stock. | 215 | 470 | 35 | 100 HB | 3.5 % IACS |
HRThis page Hot rolled | Pick for precision resistors, shunts and load cells: a 250–400 °C stabilizing bake locks in resistance and minimizes long-term drift. | 280 | 500 | 28 | 124 HB | 3.5 % IACS |
Quarter hard | Light cold work for slightly stiffer strip that must still bend and form. | 380 | 550 | 20 | 138 HB | 3.5 % IACS |
Half hard | General-purpose semi-rigid strip and rod for machined shunt bodies and terminals. | 480 | 620 | 12 | 171 HB | 3.5 % IACS |
Full hard | Hard-drawn wire and rolled strip where tensile strength and straightness matter more than bendability. | 620 | 725 | 6 | 15 HRC | 3.4 % IACS |
Extra hard | Heavily drawn wire for high-tension winding of resistance elements. | 700 | 800 | 4 | 21 HRC | 3.4 % IACS |
Spring hard | Spring-temper wire/strip for contact springs and self-supporting resistance elements. | 770 | 860 | 3 | 23 HRC | 3.4 % IACS |
Extra spring hard | Maximum-strength fine wire (typically ≤0.2 mm) produced by heavy final drawing. | 840 | 920 | 2 | 25 HRC | 3.4 % IACS |
What is C72150-HR?
C72150-HR is C72150 supplied in the HR condition — pick for precision resistors, shunts and load cells: a 250–400 °C stabilizing bake locks in resistance and minimizes long-term drift. C72150-HR has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 500 MPa (72.5 ksi) — stronger than 59% of copper alloy grades. Elongation at break is 28% and the elastic modulus is 163 GPa (23.6 Msi). C72150-HR has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,280°C (2,336 °F). O60 is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- Stiff — 163 GPa (23.6 Msi), better than 100% of copper alloy grades
- High service temperature — 500°C (932 °F), better than 99% of copper alloy grades
- Forms and bends easily — 65/100, better than 78% of copper alloy grades
- Readily welded — 60/100, better than 76% of copper alloy grades
Limitations
- Poor heat conductor — 21.5 W/m·K (12.4 BTU/hr·ft·°F), worse than 99% of copper alloy grades
- Low electrical conductivity — 3.5 % IACS, worse than 99% of copper alloy grades
- High embodied carbon — 8 kg CO₂/kg, worse than 98% of copper alloy grades
- Difficult to machine — 22/100, worse than 94% of copper alloy grades
C72150-HR properties
Typical room-temperature values for C72150-HR; 21 are specific to this condition. Other listed values are C72150 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C72150-HR has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,280°C (2,336 °F).
Mechanical13
C72150-HR has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 500 MPa (72.5 ksi) — stronger than 59% of copper alloy grades. Elongation at break is 28% and the elastic modulus is 163 GPa (23.6 Msi).
Thermal6
C72150-HR is rated for continuous service to 500°C (932 °F). It conducts heat at 21.5 W/m·K (12.4 BTU/hr·ft·°F), worse than 99% of copper alloy grades. Thermal expansion is 14.9 µm/m·K (8.28 µin/in·°F).
Electrical3
C72150-HR conducts electricity at 3.5 % IACS, worse than 99% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 69% of copper alloy grades.
Sustainability4
Producing a kilogram of C72150-HR takes about 115 MJ of energy and emits 8 kg of CO₂ — more than 98% of copper alloy grades. Typical recycled content is 20%.
Manufacturability8
C72150-HR's machinability is poor (22/100, worse than 94% of copper alloy grades); weldability good (60/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C72150-HR
Is C72150 easy to machine?
Gummy and rapidly work-hardening — use sharp positive-rake carbide, low speed (25–45 m/min), heavy feed to stay under the hardened skin, generous flood coolant and never dwell.
Can C72150 be welded?
GTAW or resistance/spot welding with matched Cu-Ni or Monel-type filler; keep sulphur, lead and oxide off the joint, use low heat input and no preheat to avoid hot cracking; welded joints locally change resistance so shunts are usually brazed/soldered instead.
Can C72150 be formed, bent or molded?
Excellent cold formability — rolls to <25 µm strain-gauge foil and draws to 0.02 mm wire; interstage anneals at 750–900 °C in reducing/inert atmosphere, then stabilizing bake at 250–400 °C to fix resistance.
What surface finishes work on C72150?
Cannot be anodized; tin, silver or nickel plate for solderability and tarnish resistance, or supply oxidized/enamelled for wound elements — clean pickling in dilute sulphuric before plating.
C72150 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 |
|---|---|---|
| NiNi+Co reported together by most mills | 43 – 46 | 45 |
| Mndeoxidizer; adjusts TCR — Chinese BMn40-1.5 uses ~1.5 Mn with 40 Ni | 0.1 – 1 | 0.5 |
| Fe | ≤ 0.5 | 0.15 |
| C | ≤ 0.05 | — |
| Simax, residual | ≤ 0.1 | — |
| Smax, kept low for weldability | ≤ 0.02 | — |
| Cu≈55 % nominal; remainder | balance | — |
C72150-HR — frequently asked
What is C72150-HR used for?
C72150-HR is typically used for thermocouple wire (type T/J/E), precision resistors, strain gauges and shunts. In short: flat resistance vs temperature; standard thermocouple negative leg; very low 3.5 % IACS conductivity.
What is the yield strength of C72150-HR?
C72150-HR has a typical yield strength of 280 MPa (40.6 ksi) and a tensile strength of 500 MPa (72.5 ksi) — stronger than 59% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C72150-HR easy to machine?
Not especially — machinability is rated poor (22/100, worse than 94% of copper alloy grades). Gummy and rapidly work-hardening — use sharp positive-rake carbide, low speed (25–45 m/min), heavy feed to stay under the hardened skin, generous flood coolant and never dwell.
Can C72150-HR be welded?
Yes — weldability is rated good (60/100). GTAW or resistance/spot welding with matched Cu-Ni or Monel-type filler; keep sulphur, lead and oxide off the joint, use low heat input and no preheat to avoid hot cracking; welded joints locally change resistance so shunts are usually brazed/soldered instead.
What surface finishes work on C72150-HR?
Cannot be anodized; tin, silver or nickel plate for solderability and tarnish resistance, or supply oxidized/enamelled for wound elements — clean pickling in dilute sulphuric before plating.
Can C72150-HR be formed, bent or molded?
Excellent cold formability — rolls to <25 µm strain-gauge foil and draws to 0.02 mm wire; interstage anneals at 750–900 °C in reducing/inert atmosphere, then stabilizing bake at 250–400 °C to fix resistance.
What is the maximum service temperature of C72150-HR?
C72150-HR is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C72150-O60 and C72150-H10?
O60 is the default condition — standard stocked condition for resistance wire, shunt strip and thermocouple wire — maximum ductility and the most stable, lowest-drift resistivity. H10: maximum-strength fine wire (typically ≤0.2 mm) produced by heavy final drawing. Yield strength is 200 MPa in O60 versus 840 MPa in H10.
Sources
- CDA/copper.org alloy datasheet C72150 — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (Copper-Nickel alloys) — ASM International (1990)
- ISOTAN® (CuNi44) resistance alloy datasheet — Isabellenhütte Heusler (2022)
- ASTM B206 — Copper-Nickel-Zinc and Copper-Nickel Alloy Wire — ASTM (2019)
- ASTM B122 — Copper-Nickel-Tin, Copper-Nickel-Zinc and Copper-Nickel Plate, Sheet, Strip and Rolled Bar — ASTM (2021)
- ASTM E230 / ANSI MC96.1 — Thermocouple EMF tables (Types T, J, E) — ASTM (2017)
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.