Schematic view of the categorical, the less we are aware of the subject. Karel Capek.
Copel — thermocouple is of copper-nickel alloy containing 43−44% nickel (Ni), 2−3% of iron (Fe), 0,5% manganese (Mn). Interest balance is copper (Cu). On its merits, this alloy is close to another copper-nickel alloy — konstantanu.
High corrosion resistance and heat resistance, can withstand heat up to 800 ° C without loss of basic qualities. It has a maximum thermal emf in a pair of copper, chromel and iron. At the same temperature coefficient — minimum. This property is inherent only to this alloy.
The physical quality
Density 8.9 g / cm³, thermal coefficient of linear expansion is 14 • 10−6 ° C-1, resistivity — 0.5 mO · mm2 / m. Thermo-emf at temperature100 ° C is 6.95 volts, and at a temperature of 600 ° C is increased to 49.0 volts. Melting point = 1290 ° C, hot working the alloy at t ° amenable to 1150 ° C, and alloy annealing is carried out at 800−850 ° C.
The main area of application is the pyrometry, therefore, the main type of wire is rolled, at least — and the circle of tape. To obtain accurate data in measuring low temperature thermocouple is used with a maximum thermal emf. For the positive electrode using copper, iron, chromel, and negative — alumel, constantan, Kopel. As the value of the thermoelectric power leads thermocouple Chromel-Kopel (TCA). It is applied at t ° up to 800 ° C, followed by copper and iron-Kopel Kopel (up to 760 ° C). Copel is also used for the manufacture of compensating wires. For this purpose, the wire is made of different diameters, but with strict technical requirements, in accordance with GOST 3044−84. The cost of the product depends on the wire diameter, the smaller the diameter, the relatively higher price.
The chemical composition of Kopel MNMts 43−0,5 in% metals
|Ni + Co||Fe||C||Si||Mn||Cu||impurities|
|42.5 — 44||≤ 0.15||≤ 0.1||≤ 0.1||0.1 — 1||54.4 — 57.4||just 0.6|
The most common brand is MNMts 43−0,5 Kopel. It comes form of a wire (diameter 0.10 — 12.0 mm), a circle (Ø 12.0 — 100.0 mm) and the thickness of the tape, which is 0.1−5.0 mm, and the width 3- 600 mm.
The physical properties of the alloy Kopel MNMTS 43−0,5 at 20 ° C
|Hardness, soft alloy HB 10 -1||Hardness, hard alloy HB 10 -1||Melting point, ° C:||hot working temperature, ° C:||Annealing Temperature, ° C:|
|= 85 — 90 MPa||= 185 MPa||1290||1000 — 1150||800 — 850|