Alloy

Chemical Composition (%)

Melting
Range
(F)

Density
(lb/in^3)
@ 68F

Thermal
Expansion
(in/in/
Fx10^6)

Electrical
Resistivity
(ohms/cir
mil/ft) 68F

Temper

52 Alloy

Ni 51.0; Fe 49.0

2600

0.298

5.4
(70-1050°F)

281

A
H/2
H

Fe Ni Co

Ni 29, Co 17, Mn 0.3, Balance Fe

2606

0.302

2.9

294

A
H/2
H

42 Alloy

Ni, Co & Cu 40.25-41.75, C 0.05 max.; Mn 1.00 max; Si 0.10-0.40; Balance Fe

2606

0.293

3.18
(0-200°F)

421

A
H/2
H

36% Nickel-Iron Alloy Invar 

(Carpenter Technology)

Ni, Co & Cu 34.50-36.50; C 0.10 max., Mn 0.50 max. Si 0.20-0.35; Balance Fe

2600

0.291

0.7
(0-200°F)

487

A
H/2
H

Ni-Span-C
(TN The International Nickel Co.)

Ni 42; Cr 5.4; Ti 2.4; Fe 48.5; Al 0.65 Allowable Maximums: C 0.06; Mn 0.80S 0.04; P 004; Si 1.00; Co 0.20

2650-2700

0.293

4.5
(-50 - +150°F)

611

A
H/2
H

Alloy

Ultimate
Tensile
Strength
(psix10^3)

Yield
Strength
(psix10^3)

Elongation
(%)

Hardness

Applications & Characteristics

52 Alloy

80
95
115

35
55
80

40
20
5

B75
B90
C20

Glass-to-metal seals.

Fe Ni Co

70
95
115

50
70
80

30
10
5

–

Glass-to-metal seals.

42 Alloy

80
100
130

35
55
85

35
20
6

B80
B90
C25

Glass-to-metal seals.

36% Nickel-Iron Alloy 

Invar (Carpenter Technology)

80
90
110

50
70
90

35
15
5

B80
B90
C25

Composite tubing for thermostatic controls.
Sometimes used for glass-to-metal sealing.

Ni-Span-C*

*(International Nickel Co.)

90
120
130

40
115
125

40
20
6

B75
B95
C25

Pressure-sensitive devices