Mechanical Properties

The addition of nickel to copper improves the alloy's strength and durability. The mechanical properties of copper-nickel alloys show a combination of good tensile strength and excellent ductility when annealed. As solid solution alloys, the 90-10 and 70-30 alloys cannot be age hardened. Higher tensile strength and hardness can only be obtained when the alloys are cold worked. Whereas 90-10 Cu-Ni tubing can have a proof strength of 100-160 N/mm2 when supplied in the annealed condition, this could typically be 345-485 N/mm2 in the as-drawn condition.

Both age hardened Cu-Ni-Al and spinodally strengthened Cu-Ni-Sn alloy systems are able to achieve high strengths matching that of carbon steel.

Typical annealed mechanical properties for copper-nickel alloys are given in Table 1. Minimum mechanical properties for 90-10 Cu-Ni (CW 352H) based on Euronorm Standards are outlined in Table 2. Minimum mechanical properties for 90-10 Cu-Ni (C70600) based on ASTM Standards are outlined in Table 3. Minimum mechanical properties for 70-30 Cu-Ni (CW 354H) based on Euronorm Standards are outlined in Table 4. Minimum mechanical properties for 70-30 Cu-Ni (C71500) based on ASTM Standards are outlined in Table 5.

Note: The following data is for guidance only. Please check values for current design specifications.

Table 1. Typical Mechanical Properties of Copper-Nickel Alloys
Alloy EN No or Other Identification UNS No 0.2% Proof Strength N/mm2 Tensile Strength N/mm2   Elongation %   Hardness  HV

Cu-Ni

CW352H

CW353H (tube only)

CW354H

C70600

C71640

C71500

100-350

150min

130-450

290-420

420min

350-520

12-40

30min

12-35

80-160

110

90-190

Cu-Ni-Cr

Def Stan 02-824 Part 1

-

-

C72200

300 min

110 min

480 min

310 min

18 min

 

Cu-Ni-Al

Cu-15Ni-3Al

 

-

 

555-630

 

770-850

 

12min

 

229-240

 

Cu-Ni-Sn

Cu-15Cr-8Sn

C72900

620-1030

825-1100

2-15

272-354
Source: Copper Alloys for Marine Environments; CDA Publication No. 206; Dec. 2012; Table 10
Table 2. Minimum mechanical properties for 90-10 Cu-Ni (CW 352H) based on Euronorm Standards
Form Condition Thickness t* Tensile Strength 0.2%Proof Strength Elongation Hardness
mm N/mm2 N/mm2 % HV

Tubes

EN 12449: 1999

 R290 20max 290 90 30 -
H075 20 max - - - 75-110
R310 6 max 310 220 12 -
H105 6 max - - - 105
R480 4 max 480 400 8
H150 4 max - - - 150

Sheet/Plate

EN 1652: 1997

 R300 0.3-15 300 (100) 20 for t<and=2.5

30 for t>2.5mm

 -
H070 0.3-15 - - - 70-120
R320 0.3-15 320 (200) 15 for >2.5mm t
H100 0.3-15 - - - 100

Plate for pressure vessels, heat exchangers

EN 1653: (1997)

 R270 2.5-125 270 100 30 (85)
R280 over10 280 110 20 (85)
R300 2.5-10 300 120 25 (90)
R320 2.5-60 320 200 15 (110)
R350 10-40 350 250 14 (120)

Figures in parentheses are not requirements but are given for information only.
1N/mm2 is equivalent to 1MPa
*For tubes t =wall thickness
Table 3. Minimum mechanical properties for 90-10 Cu-Ni(C70600) based on ASTM Standards
Form Temper Tensile Strength Yield Strength Elongation in 50mm Hardness
Standard Former MPa (N/mm2) MPa (N/mm2) % Rockwell B
Seamless Condenser Tubes B111M-98 O61 Annealed 275 105 - -
H55 Light drawn 310 240 - -
Plate Sheet Strip and Rolled Bar B122/122M-95 M20 As hot rolled 275-425 - - -
H01 Quarter hard 350-460 - - 51-78
H02 Half hard 400-495 - - 66-81
H04 Hard 490-570 - - 76-86
H06 Extra Hard 505-585 - - 80-88
H08 Spring 540-605 - - 83-91
Plate and sheet for pressure vessels, condensers and heat exchangers B171M-96 M20 and 025 (80mm and under) 275 105 30
(>60 to 140mm) 275 105 30
1N/mm2 is equivalent to 1MPa
Table 4. Minimum mechanical properties for 70-30 Cu-Ni(CW 354H) based on Euronorm Standards
Form Condition Thickness t* Tensile Strength 0.2% Proof Strength Elongation Hardness
mm N/mm2 N/mm2 % HV

Tube

EN 12449: 1999

 R370 10 max 370 120 35 -
H085 10 max - - - 85-120
R480 5 max 480 300 12 -
H135 5 max - - - 135

Sheet/plate

EN 1652: 1997

 R350 0.3-15 350-420 (120) 35 for t>2.5mm -
H080 0.3-15 - - - 80-120
R410 0.3-15 410 (300) 14 for t>2.5mm -
H110 0.3-15 - - - 110

Heavy PlateFor pressure vessels

EN 1653:1997

 R320 2.5-125 320 120 30 (100)
R410 10-40 410 300 14 (140)

Figures in parentheses are not requirements but are given for information only.
1N/mm2 is equivalent to 1MPa
*For tubes t= wall thickness
Table 5. Minimum mechanical properties for 70-30 Cu-Ni(C71500) based on ASTM Standards
Form >Temper Tensile Strength Yield Strength Elongation in 50mm Hardness
Standard Former MPa (N/mm2) MPa (N/mm2) % Rockwell B
Seamless Condenser Tubes B111M-98 O61 Annealed 360 125 - -
HR50 ( up to 1.21mm wall) Drawn, stress relieved 495 345 12 -
HR50 ( over 1.21mm wall) Drawn, stress relieved 495 345 15
Plate Sheet Strip and Rolled Bar B122/122M-95 M20 As hot rolled 310-450 - - -
H01 Quarter hard 400-495 - - 67-81
H02 Half hard 455-550 - - 76-85
H04 Hard 515-605 - - 83-89
H06 Extra Hard 550-635 - - 85-91
H08 Spring 580-650 - - 87-91
Plate and sheet for pressure vessels, condensers and heat exchangers B171M-96 M20 and 025 (80mm and under) 345 140 30
(>60 to 140mm) 310 125 30
1N/mm2 is equivalent to 1MPa

References

  1. 90/10 and 70/30 Alloys Technical Data, Publication TN 31, , CDA UK, .
  2. Copper-Nickel Alloys: Properties, Processing, Application, Booklet, German Copper Institute (DKI), English translation .
  3. Cryogenic Properties, .
  4. Fatigue of Thin-Walled Tubes in Copper Alloy CuNi10, Ships and Offshore Structures, Søren Heide Lambertsen, Lars Damkilde & Michael S. Jepsen, Ships and Offshore Structures, Vol. 11, 1, pp 1-6, , DOI: 10.1080/17445302.2014.992609, .
  5. High Strength Copper-Nickels, Tuck, C.D.S., , UK, Langley Alloys, .
  6. Mechanical Properties of Copper and Copper Alloys at Low Temperatures, Application Data Sheet 144/8 R, CDA, .
  7. Performance Advances in Copper-Nickel-Tin Spinodal Alloys, W. Raymond Cribb, Michael J. Gedeon, and Fritz C. Grensing, Advanced Materials and Processes, Vol. 171, 9, , ASM, .
  8. Properties and Uses of Copper Alloys, .
  9. The Development of Very High Strength Copper Alloys with Resistance to Hydrogen Embrittlement and Stress Corrosion Cracking, C.D.S. Tuck, , Corrosion/2005 Annual Conference and Exhibition, Houston, ©NACE, .