Nickel-Chromium Alloys

Product Type: Wire Carbon Content: Low Carbon Surface: Bright Color: Green or Silvery White Resistance: Stable Delivery Time: 10-20 Days,According to The Quantity Origin: China Material: Nichrome Treatment: Hydrogen Annealing Condition: Soft Drawing Method: Water or Oil Shape: Wire Trademark: XL HS Code: 7502200000 NIckel Resistance Wires
Electric Resistance Heating wires or strips,
Electro-thermal wires or strips,
Heating Wires

Nickel-chromium Alloys

Those are alloys of chemical composition Ni + Cr + Fe with some additional elements so as Silicium (Si) and manganese (Mn) in order to confer them an excellent behaviour when hot and an addition of rare earth in order to increase their life time.

Alloys in question are:

Resistohm 80 -70 -60 -40 -30 - 20

Their metallurgical structure confers them a very good plasticity when cold. There is a growth of the grain under heat during utilisation of the element without inducing embrittlement of it when cold. They are used for the manufacture of electric resistances for appliances (insulated elements type tubular resistances or for example opened elements on micanit plate) or for application of industrial furnaces. In addition of a relatively high specific resistance, Ni-Cr alloys join all the necessary properties for good performances in use of furnaces:

Resistance to oxidation (they are not sensitive to aggressions of humid air)
Low embrittlement at high temperature
Good plasticity - Easier to give them a shape compared with FeCrAl (lower mechanical characteristics allow indeed a good control of elasticity of the product during shaping (coiling, folding, drawing)
Good resistance to creeping (more important than ferritic alloys) which is important during conception of a resistance presenting big heights of waves. Maximal temperature recommended in the furnace: 1050 / 1100 ° C in order to obtain a reasonable life time of the elements.

Constraints:
Nevertheless, it is to be rejected in presence of a sulphurous or chlorinated atmosphere. The sulphur causes indeed breaking on nickel alloys at higher temperatures of 650 ° C ("green rot" phenomenon). For carbonaceous atmospheres, at some temperatures between 600 and 900 ° C, Ni-Cr prove less resistant than FeCrAl.

Alloy Nomenclature Performance		Cr20Ni80	Cr30Ni70	Cr15Ni60	Cr20Ni35	Cr20Ni30
Main Chemical composition	Ni	Rest	Rest	55.0-61.0	34.0-37.0	30.0-34.0
	Cr	20.0-23.0	28.0-31.0	15.0-18.0	18.0-21.0	18.0-21.0
	Fe	≤ 1.0	≤ 1.0	Rest	Rest	Rest
Max. continuous service temp. of element(º C)		1200	1250	1150	1100	1100
Resistivity at 20º C (μ Ω · m)		1.09	1.18	1.12	1.0	1.04
Density(g/cm3)		8.40	8.10	8.20	7.90	7.90
Thermal conductivity (KJ/m· h· º C)		60.3	45.2	45.2	43.8	43.8
Coefficient of lines expansion(α × 10-6/º C)		18.0	17.0	17.0	19.0	19.0
Melting point approx. ( º C)		1400	1380	1390	1390	1390
Elongation at rupture(%)		> 20	> 20	> 20	> 20	> 20
Micrographic structure		austenite	austenite	austenite	austenite	austenite
Magnetic properties		nonmagnetic	nonmagnetic	Weak magnetic	Weak magnetic	Weak magnetic

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Product Categories : NiCr Alloy