Nacobre Denomination: 71640
Designation: Copper Nickel Iron-Manganese

Condenser tubes of this alloy are giving long and dependable service at sea. It is also highly satisfactory for tubes in evaporators, inter-after condensers, air ejectors of steam condensers and in boiler feedwater heaters. This alloy is particularly desirable where high temperatures are encountered. It has the property of forming protective films of corrosion products, making it particularly desirable for service where water velocities are high. This alloy is markedly more resistant to erosion-corrosion than 706 and 715.

Copper nickel iron-manganese 71640 is one of the most corrosion resistant and durable of the copper-base alloys for condenser and heat exchanger tubes in sea water. In high pressure, high-temperature steam stations, copper nickel iron-manganese tubes are used in feedwater heaters regardless of the type of tube used in the main condensers. The high allowable design stress for this alloy qualifies it for this exacting duty.

FEASIBLE DIMENSION

AVAILABLE IN STRAIGHT LENGTHS:

 

 

 

 

W.T.

DIAMETER (INCHES)

 

(INCHES)

UP 1.00

OVER 1.0 TO 1 ½

OVER 1 ½

UP 0.040

8 TO 40 FT

8 TO 40 FT

-------

OVER 0.040

8 TO 65 FT

8 TO 50 FT

8 TO 50 FT


For other lenghts please check with the mill

CHEMICAL COMPOSITION

Alloy

Cu (%)

Ni(%)

Pb(%)

Fe(%)

Zn(%)

C71640

Remainder

29.0
to 32.0

0.02 Max.

1.7
to 2.3

0.50 Max.

Alloy

Mn(%)

P(%)

C(%)

S(%)

C71640

1.5 to 2.5

0.02 Max.

0.05 Max.

0.02 Max.

MECHANICAL PROPERTIES

Alloy

Temper

Tensile
Strength
(ksi)

Yield
Strength
(ksi)

Elongation %

C71640

O61

63 Min.

25 Min.

 

C71640

HR50

81 Min.

58 Min.

 


Alloy

Expansion
%

Grain Size
(mm)

Mercurous
Nitrate

Flattening

C71640

30 Min.

0.010 - 0.045

 

Req.

C71640

20 Min.

 

 

Req.

PHYSICAL PROPERTIES


 

UNITS

C71640

MELTING POINT
(LIQUIDUS)

°F (°C)

2260 - (1240)

MELTING POINT
(SOLIDUS)

°F (°C)

2140 - (1170)

DENSITY (TO 20°C)

Lb/cu,in

0.323

COEFICIENT OF THERMAL
EXPANSION

per °F From 68
to 572

9.0 x 10-6

THERMAL CONDUCTIVITY

Btu/sq.ft./ft/hr/°F
to 68°F

17

ELECTRICAL RESISTIVITY
(ANNEALED)

Ohms (circ.mil./ft)
to 68 °F

225

ELECTRICAL
CONDUCTIVITY
(ANNEALED)

% IACS to 68°F

4.6

THERMAL CAPACITY
(SPECIFIC HEAT)

Btu/lb/°F to 68|°F

0.09

MODULUS OF ELASTICITY
(TENSION))

Ksi

22000

MODULUS OF RIGIDITY

Ksi

8300

ANNEALED TEMPERATURE

°F (°C)

1200 –1500 -(650 – 825)

SUITABILITY FOR BEING JOINED BY


 

Alloy

Soldering

Brazing

Oxyacetylene Welding

Carbon Arc Welding

C71640

Excellent

Excellent

Good

Not recommended


 

 

 

 

 

 

Alloy

Gas Shielded
Arc Welding

Coated Metal
Arc Welding

Resistance welding

Spot

Seam

Butt

C71640

Excellent

Excellent

Excellent

Excellent

Excellent

DECIMAL EQUIVALENTS IN INCHIDES FOR VARIOUS GAGES


Gage. No.

1

2

3

4

5

6

BWG

.0.300

0.284

0.259

0.238

.0.220

0.203

AWG

0.2893

0.2576

0.2294

0.2043

0.1819

0.162

Gage. No.

7

8

9

10

11

12

BWG

0.180

0.165

0.148

0.134

0.120

0.109

AWG

0.1443

0.1285

0.1144

0.1019

0.0907

0.0808

Gage. No.

13

14

15

16

17

18

BWG

0.095

0.083

0.072

0.065

0.058

0.049

AWG

0.0720

0.0641

0.0571

0.0508

0.0453

0.0403

Gage. No.

19

20

21

22

23

24

BWG

0.042

0.035

0.032

0.028

0.025

0.022

AWG

0.0359

0.0320

0.0285

0.0253

0.0226

0.0201

 

 

 

 

NON DESTRUCTIVE TESTS AVAILABLE
EDDY CURRENT TEST
HYDROSTATIC TEST
PNEUMATIC TEST

MAXIMUM WORK PRESSURE
P = Maximum work pressure (psi)
S = Minimum tensile strength of material for an
Specific temper (It is the the value of the
Tensile strength in psi in Mechanica
Properties table)
D = Exterior diameter of tube
T = Wall thickness of tube

 

APPLICABLE STANDARDS
ASTM
ASME
BRITISH STANDARD
DIN
JIS
MIL

WEIGTH PER FEET
W= WEIGTH PER FEET( lb/ft)
D= OUTSIDE DIAMETER( in)
P= WALL THICKNESS ( in)
W= ( D-P)*P*12.18

Note: The cracking pressure is the value of 5 times the work pressure