Alkrothal® 720

StripDatasheet

Datasheet updated 2024-09-05 11:59 (supersedes all previous editions)

Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for materials under the trademark Kanthal^®.

Alkrothal^® 720 strip is a ferritic iron-chromium-aluminium alloy (FeCrAl alloy) for use at temperatures up to 1000°C (1830°F).

Typical applications for Alkrothal^® 720 strip are in rheostats, braking resistors, etc. It is also used as electrical heating elements in industrial applications.

Chemical composition

	C %	Si %	Mn %	Cr %	Al %	Fe %
Nominal composition					4.0	Bal.
Min	-	-	-	12.0	-
Max	0.08	0.7	0.7	14.0	-

Mechanical properties

Thickness	Yield strength	Tensile strength	Elongation	Hardness
	R_p0.2	R_m	A
mm (in)	MPa (ksi)	MPa (ksi)	%	Hv
1.0-3.0 (0.04-0.12)	420 (61)	550 (80)	20	200

Poisson's ratio 0.30
Mechanical properties at elevated temperature
Ultimate tensile strength - deformation rate 6.2 x 10 -2 min -1

Temperature °C (°F)	900 (1652)
MPa (ksi)	30 (4.4)

Creep strength - 1% elongation in 1000 h
Temperature °C (°F)	800 (1472)	1000 (1832)
MPa (psi)	4 (580)	1 (150)

Physical properties

Density g/cm³ (lb/in³)	7.30 (0.253)
Electrical resistivity at 20°C Ω mm²/m (Ω circ. mil/ft)	1.20 (722)
Poisson's ratio	0.30

Young's modulus
Temperature °C	20	100	200	400	600	800	1000
Temperature °F	68	212	392	752	1112	1472	1832
GPa	220	210	205	190	170	150	130
Msi	32	30	30	28	25	22	19

Temperature factor of resistivity
Temperature °C	100	200	300	400	500	600	700	800	900	1000	1100
Temperature °F	212	392	572	752	932	1112	1292	1472	1652	1832	2012
Ct	1.00	1.02	1.03	1.04	1.05	1.08	1.09	1.10	1.11	1.11	1.12

Coefficient of thermal expansion
Temperature °C (°F)	Thermal Expansion x 10^-6/ K (10^-6 /°F)
20 - 250 (68-482)	11 (6.1)
20 - 500 (68-932)	12 (6.7)
20 - 750 (68-1382)	14 (7.8)
20 - 1000 (68-1832)	15 (8.3)

Thermal Conductivity
Temperature °C (°F)	20 (68)
W m^-1 K^-1 (Btu h^-1ft^-1°F^-1)	16 (9.3)

Specific heat capacity
Temperature °C	20	200	400	600	800	1000
Temperature °F	68	392	752	1112	1472	1832
kJ kg^-1 K^-1	0.46	0.63	0.72	1.00	0.80	0.73
Btu lb^-1 °F^-1	0.11	0.15	0.17	0.24	0.19	0.17

Melting point °C (°F)	1500 (2732)
Max continuous operating temperature in air °C (°F)	1000 (1832)
Magnetic properties	The material is magnetic up to approximately 600°C (1112°F) (Curie point).
Emissivity - fully oxidized material	0.70

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