Copper Nickel Alloy 70/30 – UNS C71500 – Cupronickel

c71500 copper nickel, also known as 70/30 copper nickel, offers excellent corrosion resistance, especially in marine saltwater environments. The main wrought copper nickel alloys chosen for seawater service contain 10% or 30% nickel. This alloy has important additions of iron and manganese which are necessary to maintain good corrosion resistance.

c71500 material (CuNi30MnFe1) has limited additions of manganese and iron to increase strength. Copper nickel 70/30 is insensitive to stress corrosion.

Key properties:

Retains strength well at moderately elevated temperatures

Good cold and hot working properties

Easily weldable

Anti-bio-fouling properties in seawater

Proven anti-microbial applications in hospital environments

Although this alloy was already known in the 9th Century, it did not become popular until the 1920's when it was developed for naval applications in seawater condenser systems. The addition of iron helps grain refining and increases erosion resistance with flowing seawater.

c71500 mechanical properties for rod and bar per ASTM B151:

c71500 density = 0.323 lb/in³ (8.94 g/cm³).

Marine and Chemical:

Tube and tube plates for heavy duty water condensers

Heat exchangers

Desalination plants

Feed water heaters and evaporators in power stations

Sugar refining plants

Condenser systems

Fish cages

Cooling-water circuits and sanitary services on-board ship

Fire sprinkler systems for ships

Hydraulic and pneumatic piping

Under water sheathing

Ship building

Oil well pump liners

Salt water pumps and piping for submarines and naval surface ships

Bourdon tubes

Hydraulic fluid pipes operating under corrosive environments

Wave and tidal energy generation equipment

Mechanical:

Fasteners

Cold and hot working properties: Good

Weldability: Easily weldable

Stress corrosion: Insensitive

Iron addition function: Helps grain refining and increases erosion resistance with flowing seawater

Copper Nickel Alloy UNS C71500 is covered by the following specifications:

Material designations:

UNS: C71500, C71520

EN: CuNi30Mn1Fe, CW354H

DIN: CuNi30Mn1Fe, 2.0882

BS: CN107

France: CuNi30FeMn, CuNi30Mn1Fe

Japan: C7150

Russia: MNZMc30-1-1

China: BFe30-1-1

Australia: 715

Q1: What is the difference between C71500 and C70600 copper nickel?

C71500 has higher strength and better erosion resistance than C70600. C71500 contains 30% nickel with iron and manganese additions for increased strength. C70600 contains 10% nickel. The page notes C71500 retains strength well at elevated temperatures and is insensitive to stress corrosion. For high-velocity seawater above 3.5 m/s, choose C71500. For lower velocity, C70600 is more economical.

Q2: What welding methods work for C71500 copper nickel?

C71500 is easily weldable with good cold and hot working properties. The page states the alloy has "good cold and hot working properties" and is "easily weldable." For C71500 copper pipe, TIG welding with ERNi-7 filler metal and argon back-purge is recommended. Avoid overheating as it can reduce corrosion resistance.

Q3: Why does C71500 contain iron and manganese?

Iron and manganese are added to increase strength and corrosion resistance. The page states C71500 (CuNi30MnFe1) has "limited additions of manganese and iron to increase the strength." Iron specifically helps grain refining and increases erosion resistance with flowing seawater. Without these additions, 70/30 cupronickel loses its marine-grade performance.

Q4: What is the density of C71500 material?

C71500 density is 0.323 lb/in³ (8.94 g/cm³). For C71500 copper pipe weight calculation: (OD - wall) × wall × 10.68 = lb/ft. This density contributes to pressure tightness and acoustic damping in piping systems.

Q5: What is the melting range of C71500?

Melting range is 2140-2260°F (1170-1240°C). Solidus is 2140°F, liquidus is 2260°F. Hot working range is 1695-1875°F (925-1025°C). This relatively high melting point allows C71500 to retain strength at moderately elevated temperatures.

Q6: Is C71500 suitable for desalination plants?

Yes, C71500 is used in desalination plants. The page lists "desalination plants" as a key application. The alloy's resistance to seawater corrosion and bio-fouling makes it suitable for both multi-stage flash and multiple effect distillation plants. Applications include heat exchangers and evaporator tubes.

Q7: Does C71500 have anti-microbial properties?

Yes, C71500 is registered with the US EPA as an antimicrobial alloy. The page states: "Registered with the USA EPA as an Antimicrobial Alloy." Being high in copper, C71500 has anti-bio-fouling properties in seawater and has been proven to have anti-microbial applications in hospital environments to combat the spread of viral bacteria.

Q8: What military specifications cover C71500?

MIL-C-15726, MIL-T-15005, and MIL-C-24679 cover C71500. The page lists these military specifications. For naval applications including submarines and surface ships, these MIL specs apply. Also available to Def Stan 02-780 for UK military applications.

Q9: What forms of C71500 are available?

Round, rectangular, and sleeve shapes are available. The page lists these three forms. Through ASTM specifications, C71500 is also available as tube, pipe, sheet, plate, strip, rod, bar, wire, and forgings per the specifications table.

Q10: What are the typical applications for C71500 in marine environments?

Salt water pumps and piping for submarines and naval surface ships, underwater sheathing, fire sprinkler systems for ships, and hydraulic fluid pipes under corrosive environments. The page lists these as key marine applications. The alloy was originally developed for naval applications in seawater condenser systems in the 1920s.

Marking per bundle: Alloy (C71500 / 70/30), heat number, size (OD × wall), length, quantity, PO number, net/gross weight.

Moisture protection: Desiccant bags for tropical or long-term storage.

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