Nickel Iron Alloys

 

NiFe 70/30 & NiFe 52/48

 

This effect has the following advantages:Nickel Iron alloys have been developed to produce high temperature coefficients of resistance (Positive Temperature Coefficient or PTC) in order to provide a ‘self-limiting’ heating wire.  When the temperature of the wire is around 250 °C the element resistance will have doubled and the power output will have halved. 

 


·        Improved temperature control,

·        Reduced energy consumption,

·        Reduced power if overheating,

·        High start-up power.



Nickel Iron Alloys are available in sizes down to 0.09 mm.

Physical and Mechanical Properties


 

Units

NiFe 70/30

NiFe 52/48

Maximum continuous operating temperature in air

°C

°F

600

1100

600

1100

Nominal composition

%

Ni 70

Fe 30

Ni 52

Fe 48

Density at 20°C

g/cm³

lb/in³

8.45

0.305

8.20

0.296

Resistivity at 20°C

µWcm

W/cmf

21

130

37

220

Coefficient of thermal expansion,

20 – 100°C

68 – 212°F

1/K

1/°F

15 x 10-6

8.3 x 10-6

10 x 10-6

5.6 x 10-6

Thermal conductivity at

20°C

68°F

W/mK

Btu.in/ft².h.°F

17

120

17

120

Specific heat capacity at

20°C

68°F

kJ/kgK

Btu/lb°F

0.52

0.12

0.50

0.12

Melting point (approx.)

°C

°F

1430

2610

1435

2620

Magnetic properties (up to Curie point)

 

Magnetic

Magnetic

Curie point

°C

°F

610

1130

530

990

Tensile strength Rm(0.5 mm wire)

N/mm²

lb/in²

640

93000

610

88000

Yield point Rp0.2(0.5 mm wire)

N/mm²

lb/in²

340

49000

340

49000

Elongation at break (approx.) (0.5 mm wire)

%

30

30


Temperature Factors

Temp °C

100

150

200

250

300

350

400

450

500

Temp °F

212

302

392

482

572

662

752

842

932

70/30 Ni/Fe

1.35

1.57

1.80

2.05

2.30

2.56

2.82

3.10

3.40

52/48 Ni/Fe

1.33

1.53

1.73

1.93

2.13

2.32

2.49

2.64

2.77


Information contained within this technical data sheet is based upon the general experience of Scott Precision Wire Ltd and is believed to be correct at the time of issue. 

No warranty is given or is to be implied from  the details above. 

Customers are advised to carry out independent tests in order to determine the suitability of any Scott Precision Wire Ltd product for an application.

 

To print this page please open NiFe Alloys.pdf