Description
Other alloying elements like zinc, silicon, lead, etc are also added at times to attain the required properties. The overall chemical composition of the grade provides fine strength and ductility. The common wrought forms of the grade are sheets, plates, and tubes. However, the grade has fine machining characteristics and can be readily fabricated to a required form. It has become a popular choice in marine, construction, and various industrial applications. The grade can be used at elevated temperatures but in a controlled manner. Moderate strength is retained at elevated temperatures.
The grade manages to provide thermal stability at elevated temperatures. It can also be suitably used at lower temperatures, even down to cryogenic temperatures, as it retains its mechanical properties. The grade has fine resistance to creep and fatigue properties. It passed the reverse bending test and also the required test for the designated creep rate in the alloy at moderate to elevated temperatures. It can thereby be used in dynamic applications. There is often an unwanted influx of hydrogen in the microstructure during processes like forming.
This leads to embrittlement of the material. The copper-nickel grade has fine resistance to hydrogen embrittlement and it is relatively used in respective applications. The grade also has applications in highly hygienic and sanitary environments since it readily kills 99.9% of unwanted microorganisms including viruses. It has commendable antimicrobial properties. Hence, it has high-end applications in healthcare environments. The grade has fine hot working as well as cold working capability, hot working processes can be done on the grade at around 850-950°C.
Chemical Properties
| Grade | Cu | Fe | Pb | Mn | Ni | Zn | |
| 90-10 | Min./Max. | Rem. | 1.0-1.8 | .05 | 1.0 | 9.0-11.0 | 1.0 |
| Nominal | 88.6 | 1.4 | – | – | 10.0 | – |
Physical Properties
| Density | 8.94 g/cm3 0.323 lb/in3 |
| Elastic Modulus | 140 GPa 20300 ksi |
| Poissons Ratio | 0.34 |
| Melting Point | 1170 to 1240oC or 2140 to 2265 oF |
| Shears MODULUS (N/MM2) | 52.0 GPa 7540 ksi |
| Specific heat capacity | 0.09 cal/goC or 0.09 Btu/lb oF |
| Thermal conductivity | 0.12 cal cm/cm2 s oC or 29 BTU ft/ft2 h oF |
| Electrical conductivity at -269oC or -452oF (annealed) | 5.8 microhm mm2 or 10% IACS |
General Data
| Standard | 90-10 |
| UNS | C70600 |
| WERKSTOFF NR. | 2.0872 |
| EN | 12449 CuNi10Fe1Mn |
| BS | CN102 |
| DIN | CuNi10Fe1Mn |
| AFNOR | CuNi10Fe1Mn |
Standards Specifications
PIPES & TUBES
| Summary | Standards |
| Standard Specification for Copper and Copper-Alloy Seamless Condenser Tubes and Ferrule Stock | ASTM B111 |
| Standard Specification for Copper and Copper-Alloy Seamless Condenser and Heat Exchanger Tubes With Integral Fins | ASTM B359 |
| Standard Specification for U-Bend Seamless Copper and Copper Alloy Heat Exchanger and Condenser Tubes | ASTM B395 |
| Standard Specification for Welded Copper-Nickel Pipe | ASTM B467 |
| Standard Specification for Welded Copper and Copper-Alloy Heat Exchanger Tube | ASTM B543 |
| Standard Specification for Seamless and Welded Copper–Nickel Tubes for Water Desalting Plants | ASTM B552 |
Forms of Supply
Piping and tubing, fittings and flanges, washers.
Corrosion Resistance
The copper-nickel grade has excellent resistance to seawater, brackish water, and flow of water having air bubbles and turbulent flow. It also has fine resistance to biofouling in seawater. It readily resists phosphoric acid, sulphuric acid, and other mild organic acids. When tested under moist air or steam, the grade visibly shows fine oxidation resistance. The inclusion of iron and manganese in the grade further enhances the corrosion resistance properties and even provides the required resistance for stress cracking. It also provides the required resistance to chlorides, sulfates, nitrates, and ammonium compounds.
Heat Treatment
The grade is annealed appropriately for the removal of internal stresses. It is done around 600-820°C, followed by proper quenching. Thorough soaking and time at the temperature at every section are managed meticulously. Nickel is soluble in the copper phase. However, other alloying elements do not get homogenized in the grain structure even after thermal treatment.
Weldability
The grade is readily weldable using techniques like gas spot welding, oxyacetylene welding, shielded arc welding, brazing, coated metal arc welding, butt welding, soldering, and seam welding processes. There is no carbon content in the grade and hence the welding techniques used in this grade are different than that of austenitic and ferritic grades.
Machining
The grade has fine machining and fabricating properties. The normal machining rate of the grade is 20%. Positive feeds, powerful machinery, adequate lubrication, and rigid tooling are recommended. They are often machined and forged as pump and valve parts to be used in various services.
Applications
Marine hardware, Underwater tubing, Power steering tube, brake lines, condenser plates, valve and pump components, Fish cages for aquaculture, Desalination units, Seawater pipework, pressure vessels and distiller tubes, hot water tanks, saltwater baffles, propeller sleeves, flanges, boat hulls, marine fittings and marine hardware, Offshore fire water systems, cooling plant, evaporator tubes, Tubes for power plants and ships, Hydraulic lines, Heat exchangers and condensers.
Possible Grade Alternatives
GRADE COPPER NICKEL 70/30
| Grade | Cu | Fe | Pb | Mn | Ni | Zn | |
| 70-30 | Min./Max. | Rem. | 0.4-1.0 | 0.05 | 1.0 | 29.0-33.0 | 1.0 |
| Nominal | 69.5 | 0.50 | – | – | 30.0 | – |
