Fechral Cr27Al5Тi

Cold drawn wire from the alloy Cr27Al5Тi used for the resistance elements and heaters. Cr27Al5Тi has excellent resistance to high electrical resistance and low temperature coefficient of electrical resistance (ТCER), low ТCER and a high strain-sensitivity, good plasticity and excellent heat-resistance.

The alloy has a high maximum working temperature (to 1350 °C) and 2-4 times more durable in comparison with the Nichrome at exploitation at high temperatures (1000-1350 °C) in oxidation, sulfur and others environments. The alloy exhibits stable ТCER that let support the temperature of heater systems. Using Cr27Al5Тi, having less specific gravity and higher specific resistance in compare with Nichrome that let reduce the weight of heating material in 20-30% the same length and diameter of the wire, and also have result more equal heating at the length. Reducing the weight results to cut costs by miniaturizing the lining, fixturing etc.

New technology of producing Cr27Al5Тi provides it homogeneous structure, uniformity of protective oxide layer and high adhesion layer to the surface. In combination with reduction of bases carbon to the level ≤0.03%,is guaranteed the high wire plasticity, the absence inclination to intergranular high temperature corrosion, high creep limit, and also oxide resistance, Al2О3 is gathered on the surface of the alloy serving as good insulator and prevent the corrosion more effective in compare to green rouge (Cr2O3), was having on the surface of Nichrome.

Fields of applications

Electric heating of the furnaces are for all branches of industry, household appliances etc. Cr27Al5Тi used in high temperature electric furnaces, firing furnaces and fire drying furnaces, different electric heaters. Having enhanced, creep resistance, ductility, (including after long exploitation), stability of the form and increased term of exploitation.

Technical information:

Cold-drawn wire from the alloy Cr27Al5Ti is produced in soft thermally manufactured diameter 0.1-10 mm according to DIN 17470.

Limiting deflections in diameter of the wire not exceed ±0.100 mm, and the oval of the wire is not more than half of the field tolerance in diameter.

Chemical composition of alloy and typical mechanical and physical properties of the alloy Cr27Al5Ti are in the table:

Chemical composition, % :
С	≤ 0,05
Cr	21 - 23
Аl	5 - 6
Si	< 0,6
Mn	<0,5
Zr	< 0,3
S	< 0,005
P	< 0,02
Fe	основа

Mechanical and special properties::
Tensile Strength, MPa	700-800
Yield Strength, МPа	510-610
Elongation, %	14-23
Density, g/сm3	7,1
Curie point	~600 °C
Melting temperature	1500 °C
Specific electric resistance Оm/mm2/m at 20°C	1,44
Transmissibility in conditions absolute oxidation	0,70

Durability of the alloy, tested the method G, at temperature 1300 °C, compose not less 100hours

Advantages:

• High temperature of exploitation – to1350 °C, against 1200 °C for Cr20Ni80.


• High melting temperature - 1500 °C, against 1400 °C for Cr20Ni80.


• Term of employment in 2-4 times longer than nichrome.


• Not high density - 7.10 g/сm³ against 8.4g/сm³ for Cr20Ni80, let economize to 18% on the weight..


• The best corrosion - resistance in the air, vacuum, argon, sulfur and carbon content mediums, water steam.


• High yield strength, let use the wire minimum diameter in connection less changed square cross-section at the coiling.


• High specific resistance – 1.39 Оm*mm²/m against 1.12 for Cr20Ni80.


• Electric resistance does not depend from different forms of heat influence and cold warping.


• Unique correlation of tensile strength or yield strength (~0.5), let use this sphere elastic-plastic deformation.