Copper Nickel Vs Stainless Steel

Copper Nickel Vs Stainless Steel

Let's understand the basic structural, uses, properties and Price difference between Copper Nickel and Stainless Steel

Know the the most basic Difference Between Copper Nickel and Stainless Steel and Price Difference Between Copper Nickel and Stainless Steel

Copper Nickel Vs Stainless Steel

Copper nickel, also known as Cupronickel is an alloy of metals copper and nickel. As the name suggests, copper (85 % – 90%) forms majority of the alloy followed by nickel (9% - 11%) along with trace minerals like Ferrous or Iron (1% - 2%) and Manganese (0.3% - 1%). Copper Nickel alloy can also be formed in the 70/30 percent by adjusting the metal content accordingly. Here we have mentioned useful information to check the difference between copper nickel and stainless steel alloys. Compare Copper Nickel Vs Stainless Steel in terms of composition, machinability, specifications, properties, price difference and uses.

Stainless steel is a Steel alloy with the addition of metals like chromium, carbon, silicon, nickel, Molybdenum & manganese. It is also known as inox steel. Around 10% of this alloy is made up of chromium. Chromium produces a thin oxide layer on the surface of stainless steel, called the ‘passive layer’. This passive layer and the addition of metals like nickel & Molybdenum, prevent the oxidation of Ferrous or in simple terms rusting of Iron. There are more than 100 grades of steel, which can be classified into 5 groups – viz. austenitic, ferritic, martensitic, duplex, and precipitation-hardening.

Austenitic Stainless steel is the most produced steel, consisting of about two-thirds of all stainless-steel production. The structure of this steel is a cube, which gives them excellent formability and weldability and they are ductile at cryogenic (extremely low) temperatures. And they are non-magnetic.

Ferritic steels have a high content of chromium and a low content of carbon. They are magnetic & have good ductility, resistance to corrosion and stress corrosion cracking. Martensitic stainless steels, named after the German metallurgist Adolf Martens, are formed by rapid cooling of austenite iron. Duplex stainless steels have a structure similar to that of austenite and ferrite stainless steel.

Origins.

The earliest record for Copper Nickel production dates back to about 300 BCE in China. The description of the process in these records mentioned heating and mixing copper, nickel and saltpetre (potassium nitrate) together to form an alloy. Post the civil wars in the US, coins were made from this alloy.

Steel chrome alloys were first noted for their corrosion resistance in 1821 by Pierre Berthier. ln 1912, Sheffield based metallurgist Harry Brearley was credited with the invention of stainless steel. He observed that stainless steel did not get corroded while trying to make ammunitions.

Copper Nickel Properties & Applications

Copper Nickel is silver in colour, despite its high copper content. Copper on its own is reddish brown coloured metal. The change in colour is due to the loss of 1 electron in the last shell of the orbit, making it an electro negative atom.

Copper Nickel is highly ductile and malleable. Ductility refers to the ability of a metal to be drawn into a thin wire and malleability refers to the ability of a metal to be moulded in any particular shape without breaking. Hence it is used to produce industrial grade wires, tubes, pipes, rods, sheets, etc. Copper Nickel is resistant to corrosion by microfouling (algae, fungi etc) and saline (sea) water, making it the perfect alloy for marine applications. For example, manufacturing welding electrodes, boat hulls, marine condenser tubes, heat exchangers, brake lines, pipe fittings, valves and fasteners. Unlike stainless steel, which is easily corroded by biofouling. Copper nickel has good tensile strength and is a good conductor of electricity.

Coins are made from Copper Nickel in the 70/30 ratio, because of its high durability and no-tarnish property.

Today, the use of stainless steel has been tremendous as many industries rely on the alloy for production of various resources. From construction of buildings, architecture to automobile, transport, medicine etc, these industries have about 15 grades of stainless steel for day to day production. Because of its good looks, stainless steel used in construction of skyscrapers, airports, bridges, sculptures, etc. The culinary uses of stainless steel include production of kitchen sinks, cutlery, cook ware, while its automotive and aerospace applications include construction of auto parts, railcars, aircrafts etc.

Some other applications of stainless steel include industrial equipment (for example, in paper mills, chemical plants, water treatment); and storage tanks and tankers for chemicals and food products (for example, chemical tankers and road tankers). Although stainless steel is generally non corrosive to most chemicals, it is affected by the presence of chorine compounds in water. Hence after using the equipment, it needs to be cleaned thoroughly. While copper nickel remains unaffected by chorine particles, it can get corroded in the presence of ammonia.

The appearance of this alloy is silver grey. Like Copper Nickel, stainless steel has good ductility, is very malleable, has high tensile strength and good lustre. Stainless steel is not a good conductor of electricity. While both these alloys have varying composition, they are 100% recyclable.

Price of Copper Nickel Vs Stainless Steel per kg

Stainless Steel and Copper Nickel Price per kg Origin Price in USD (per kg)
Stainless Steel Price per kg in India (grade 304) Indian $2.85
Copper Nickel Price per kg in India (CuNi 90/10) Indian $6.00

All Stainless Steel grades Equivalents

STANDARD WERKSTOFF NR. UNS JIS BS GOST AFNOR EN
Stainless Steel 304 1.4301 S30400 SUS 304 304S31 08X18H10 Z7CN18-09 X5CrNi18-10
Stainless Steel 304L 1.4306/1.4307 S30403 SUS 304L 304S11 03X18H11 Z3CN18-10 X2CrNi18-9 / X2CrNi19-11
Stainless Steel 310 1.4845 S31000 - - - - -
Stainless Steel 310S 1.4845 S31008 SUS310S - 20Ch23N18 - X8CrNi25-21
Stainless Steel 316 1.4401 / 1.4436 S31600 SUS 316 316S31 / 316S33 - Z7CND17-11-02 X5CrNiMo17-12-2 / X3CrNiMo17-13-3
Stainless Steel 316L 1.4404 / 1.4435 S31603 SUS 316L 316S11 / 316S13 03Ch17N14M3 / 03Ch17N14M2 Z3CND17-11-02 / Z3CND18-14-032 X2CrNiMo17-12-2 / X2CrNiMo18-14-3
Stainless Steel 317 1.4449 S31700 SUS 317 - - - X6CrNiMo19-13-4
Stainless Steel 317L 1.4438 S31703 SUS 317L - - - X2CrNiMo18154
Stainless Steel 321 1.4541 S32100 SUS 321 - 08Ch18N10T - X6CrNiTi18-10
Stainless Steel 321H 1.4541 S32109 SUS 321H - - - X6CrNiTi18-10
Stainless Steel 347 1.4550 S34700 SUS 347 - 08Ch18N12B - X6CrNiNb18-10
Stainless Steel 347H 1.4961 S34709 SUS 347H - - - X7CrNiNb18-10
Stainless Steel 446 1.4762 S44600 - - - - -

Stainless Steel Chemical Composition (All Stainless Steel Grades at a glance)

Grade C (max) Mn (max) Si (max) P (max) S Cr Mo Ni N
Stainless Steel 304 0.08 2 0.75 0.040 0.030 18 - 20 - 8 - 11 -
Stainless Steel 304L 0.03 2 0.75 0.045 0.030 18 - 20 - 8 - 12 0.10
Stainless Steel 310 0.25 2 1.50 0.045 0.030 24 - 26 - 19 - 22 -
Stainless Steel 310S 0.08 2 1.50 0.045 0.030 24 - 26 - 19 - 22 -
Stainless Steel 316 0.08 2 0.75 0.045 0.030 16 - 18 2 - 3 10 - 14 0.1 max
Stainless Steel 316L 0.3 2 0.75 0.045 0.030 16 - 18 2 - 3 10 - 14 0.10 max
Stainless Steel 317 008 2 1 0.040 0.03 18 - 20 3 - 4 11 - 14 0.10 max
Stainless Steel 317L 0.035 2 1 0.040 0.03 18 - 20 3 - 4 11 - 15 -
Stainless Steel 321 0.08 2 0.75 0.045 0.03 17 - 19 5xC min
0.60% max
9 - 12 0.10 max
Stainless Steel 321H 0.04 - 0.10 max 2 0.75 0.045 0.03 max 17 - 19 4xC min
0.60% max
9 - 12 0.10 max
Stainless Steel 347 0.08 max 2 0.75 0.045 0.03 max 17 - 20 10xC min
1.00 max
9 - 13 62.74
Stainless Steel 347H 0.04 - 0.10 2 0.75 0.045 0.03 max 17 - 20 8xC min
1.00 max
9 - 13 62.74
Stainless Steel 446 0.2 max 1.5 0.75 0.040 0.03 max 23 - 30 0.10 - 0.25 0.50 max Balance

Check Stainless Steel Melting Point, Density and Tensile Strength

Grade Density Melting Point Tensile Strength (Psi) Yield Strength (0.2%Offset) (Psi) Elongation
Stainless Steel 304 8.0 g/cm3 1400 °C (2550 °F) 75000, MPa - 515 30000, MPa - 205 35 %
Stainless Steel 304L 8.0 g/cm3 1400 °C (2550 °F) 75000, MPa - 515 30000, MPa - 205 40 %
Stainless Steel 310 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 35 %
Stainless Steel 310S 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 35 %
Stainless Steel 316 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 35 %
Stainless Steel 316L 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 40 %
Stainless Steel 317 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 35 %
Stainless Steel 317L 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 35 %
Stainless Steel 321 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 35 %
Stainless Steel 321H 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 35 %
Stainless Steel 347 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 40 %
Stainless Steel 347H 8.0 g/cm3 1454 °C (2650 °F) 75000, MPa - 515 30000, MPa - 205 40 %
Stainless Steel 446 7.5 g/cm3 1510 °C (2750 °F) 75,000, MPa - 485 40,000, MPa - 275 20 %

Copper Nickel Specification

Copper Nickel Product Specification
Copper Nickel Bar ASTM B122, B151, MILITARY MIL-C-15726, SAE J461, J463
Copper Nickel Bolts ASTM F468
Copper Nickel Electrode, Welding AWS A5.6, MILITARY MIL-E-22200/4
Copper Nickel Nuts ASTM F467
Copper Nickel Pipe, Seamless ASME SB466, ASTM B466
Copper Nickel Pipe, Welded ASTM B608, B467
Copper Nickel Plate ASTM B122, MILITARY MIL-C-15726, SAE J461, J463
Copper Nickel Plate, Clad ASTM B432
Copper Nickel Plate, Condenser Tube ASME SB171, ASTM B171, SAE J463, J461
Copper Nickel Rod ASTM B151, MILITARY MIL-C-15726
Copper Nickel Screws ASTM F468
Copper Nickel Sheet ASTM B122, MILITARY MIL-C-15726, SAE J463, J461
Copper Nickel Strip ASTM B122, MILITARY MIL-C-15726, SAE J461, J463
Copper Nickel Studs ASTM F468
Copper Nickel Tube, Condenser ASME SB111, ASTM B552, B111, MILITARY MIL-T-15005, SAE J463, J461
Copper Nickel Tube, Finned ASME SB359, ASTM B359, MILITARY MIL-T-22214
Copper Nickel Tube, Seamless ASME SB466, ASTM B466, MILITARY MIL-T-16420
Copper Nickel Tube, U-Bend ASME SB395, ASTM B395
Copper Nickel Tube, Welded ASME SB543, ASTM B543
Copper Nickel Wire MILITARY MIL-C-15726

Physical & machinability Properties of Copper Nickel

Property Metric Units Imperial Units
Melting Point (Liquidus) 11,500°C 21,000°F
Melting Point (Solidus) 11,000°C 20,100°F
Density 8.94 gm/cm³ @ 20°C 0.323 lb/in³ @ 68°F
Specific Gravity 8.94 8.94
Coefficient of Thermal Expansion 17.1 x 10 -6 / °C (20-300°C) 9.5 x 10 -5 / °F (68-392°F)
Themal Conductivity 40 W/m. °K @ 20°C 23 BTU/ft³/ft/hr/ °F @ 68°F
Thermal Capacity (Specific Heat) 380 J/kg. °K @ 20°C 0.09 BTU/lb/ °F @ 68°F
Electrical Conductivity (Annealed) 5.26 microhm .cm @ 20°C 9.1% IACS
Electrical Resistivity (Annealed) 0.190 microhm.cm @ 20°C 130 ohms (circ mil/ft) @ 68°F
Modulus of Elasticity (tension) 140 GPa @ 20°C 20 x 10 6 psi @ 68°F
Modulus of Rigidity (torsion) 52 GPa @ 20°C 7.5 x 10 6 psi @ 68°F

Environmental Properties of Copper Nickel

Resistance Factors
1=Poor 5=Excellent
Flammability 5
Fresh Water 5
Organic Solvents 5
Oxidation at 500C 3
Sea Water 5
Strong Acid 2
Strong Alkalis 5
UV 5
Wear 5
Weak Acid 4
Weak Alkalis 5

 

Summary

While both copper nickel and stainless steel alloys have different metals, the applications of the alloy to be used is dependent on the end use of the product. Hope this article help you to resolve all your queries regarding Copper Nickel Vs Stainless Steel.

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