Copper Alloy C72150
UNS C72150 · EN CuNi44Mn1 · GB BMn40-1.5
Nominally 55Cu-45Ni alloy (Constantan) valued for its nearly flat resistance-vs-temperature curve and high thermoelectric output against copper/iron, standard for thermocouples and precision resistors.
Reference datasheet — C72150 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the O60 condition
C72150 tempers and conditions
C72150 is supplied in 9 conditions, soft to hard. O60 is the default FabDigit quotes; the values on this page are for it.
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 |
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?
Nominally 55Cu-45Ni alloy (Constantan) valued for its nearly flat resistance-vs-temperature curve and high thermoelectric output against copper/iron, standard for thermocouples and precision resistors. C72150 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). C72150 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 54% of copper alloy grades. Elongation at break is 38% and the elastic modulus is 162 GPa (23.5 Msi).
What is C72150 used for?
- thermocouple wire (type T/J/E)
- precision resistors
- strain gauges
- shunts
Advantages
- Stiff — 162 GPa (23.5 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 — 85/100, better than 85% of copper alloy grades
- Ductile — tolerates forming and impact — 38%, better than 82% of copper alloy grades
- Readily welded — 60/100, better than 76% of copper alloy grades
Limitations
- Poor heat conductor — 21 W/m·K (12.1 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 — 25/100, worse than 86% of copper alloy grades
C72150 properties
Typical room-temperature values for C72150-O60; bars are the position among copper alloy grades.
Physical3
C72150 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 has a yield strength of 200 MPa (29 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 54% of copper alloy grades. Elongation at break is 38% and the elastic modulus is 162 GPa (23.5 Msi).
Thermal6
C72150 is rated for continuous service to 500°C (932 °F). It conducts heat at 21 W/m·K (12.1 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 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 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's machinability is poor (25/100, worse than 86% of copper alloy grades); weldability good (60/100); formability excellent (85/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C72150 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C72150
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.
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 |
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.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Equivalent designations
Standards and trade names that resolve to Copper Alloy C72150 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- CuNi44Mn1
- GB (China)
- BMn40-1.5
- Also called
- Constantan
How much does C72150 cost?
C72150 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C72150 — frequently asked
What is C72150 used for?
C72150 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?
C72150 has a typical yield strength of 200 MPa (29 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 54% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C72150 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 86% 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 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?
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 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?
C72150 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.
How much does C72150 cost?
C72150 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.