Alumel is a nickel alloy so Ni is its main chemical component. Besides nickel alumel contains 0.6-1.2% of cobalt (Co); 1.6-2.4% of aluminium (Al); 1.8-2.7% of manganese (Mn); 0.85-1.50% of silicon (Si). The admixture content is 0.7% and includes arsenic (As), carbon (C), iron (Fe), phosphorus (P), lead (Pb), sulphur (S) and other substances. In standards, alumel is designated as NMtsAK 2-2-1.
Properties
С точки зрения применения в промышленности алюмель можно классифицировать как термоэлектродный материал. Соответственно, он должен иметь ряд характеристик, необходимых для работы в определенных условиях. К ним относятся: высокая термо-ЭДС, достаточная температура плавления, хорошая коррозионная стойкость, а также механическая прочность и пластичность.
Physical properties
Property
Value
Melting temperature, °С
1400
Density, kg/m3
8670
Specific resistance, Ohm·m·108
33±5
Average temperature coefficient of resistance (20-100 °С), °С-1·104
23.9
Average thermal expansion coefficient (20-100 °С), °С-1·106
12.0
Magnetic behavior
Слабо ферромагнитен
Curie point, °С
170
Some values of physical properties depend on material temperature.
Temperature-dependant properties
Property
T, °С
20
200
400
600
800
1000
1200
Specific resistance, Ohm·m·10-8
33
47
54
60
65
71
77
Ratio of resistance under t to resistance under 20 °С
1.00
1.43
1.64
1.82
1.98
2.15
2.32
Average thermal expansion coefficient (20-t °С), °С-1·10-6
-
12.2
12.6
13.6
14.7
15.8
16.9
Specific heat, kJ/(kg·К)
0.475
0.489
0.503
0.518
0.538
0.548
0.564
Heat conductivity, W/(m·К)
26.8
29.3
35.2
40.2
44.4
47.7
-
Alloy mechanical properties
Property
Value
Ultimate tensile strength, MPa
550-660
Yield point, MPa
190-230
Percentage of elongation, %
28-38
Reduction in area, %
68-78
Brinell hardness
120-130
Applications
Alumel is used for producing thermocouple electrodes and extension sets. It is also used for producing TChA thermocouple cathodes (chromel-alumel) and compensating leads (extension sets) for it.
Calculate the weight of products made of thermocouple alloys
