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®.
Kanthal® APMT tubes is an advanced powder metallurgical, dispersion strengthened, ferritic iron-chromium-aluminium alloy (FeCrAlMo alloy) which is used at tube temperatures up to 1250°C (2280°F).
Kanthal® APMT tubes have good form stability at high temperature. Kanthal® APMT forms an excellent, non-scaling surface oxide, which gives good protection in most furnace environments, i.e. oxidizing, sulphurous and carburizing, as well as against deposits of carbon, ash, etc. The combination of excellent oxidation properties and form stability makes the alloy unique.
Typical applications for Kanthal® APMT are as radiant tubes in electrically or gas fired furnaces such as continuous annealing and galvanizing furnaces, seal quench furnaces, holding furnaces and dosing furnaces in the aluminium, zinc, lead industries, thermocouple protection tubes, furnace muffles for sintering applications.
C %
Si %
Mn %
Mo %
Cr %
Al %
Fe %
Nominal composition
3.0
21.0
5.0
Balance
Min
-
-
-
20.5
-
Max
0.08
0.7
0.4
23.5
-
Maximum recommended operating temperature in air °C (°F)
1250 (2280)
Protective surface oxide
Al2O3
Oxidation rate
Weight gain of Kanthal APMT, due to oxide formation, when oxidized in air at 1200°C for 100h cycles with cooling to ambient temperature between each cycle.
Yield strength
Tensile strength
Elongation
Hardness
Rp0.2
Rm
A
MPa (ksi)
MPa (ksi)
%
Hv
540 (78)
740 (107)
26
250
Remark: The samples are taken in the longitudinal direction from tube in delivery condition.
Mechanical properties at elevated temperature
Creep strength - 1% elongation in 1000 h
Temperature °C F)
800 (1472)
900 (1652)
1000 (1832)
1100 (2012)
1200 (2192)
MPa (ksi)
21.9 (3200)
15.6 (2300
10.9 (1600)
5.0 (730)
2.1 (300)
Remark: The samples are taken in the longitudinal direction from tube in delivery condition. Typical typical initial average grain size is 30-50μm.
Secondary creep rate at various stress levels
Creep rate
Temperature / Stress
s-1
800°C (1472°F)
900°C (1652°F)
1000°C (1832°F)
1100°C (2012°F)
1200°C (2192°F)
MPa (psi)
MPa (psi)
MPa (psi)
MPa (psi)
MPa (psi)
1.0 e-10
20.7 (3000)
12.7 (1800)
7.7 (1100)
3.0 (440)
1.2 (170)
1.0 e-8
25.5 (3700)
18.0 (2600)
13.0 (1900)
6.9 (1000)
3.0 (440)
1.0 e-6
30.8 (4500)
25.5 (3700)
22.2 (3200)
16.2 (2300)
7.3 (1100)
Creep rupture strength
Time
Temperature / Stress
h
800°C (1472°F)
900°C (1652°F)
1000°C (1832°F)
1100°C (2012°F)
1200°C (2192°F)
MPa (psi)
MPa (psi)
MPa (psi)
MPa (psi)
MPa (psi)
100
28.8 (4200)
22.0 (3200)
17.9 (2600)
10.1 (1500)
5.0 (730)
1000
25.3 (3700)
17.3 (2500)
12.3 (1800)
6.0 (870)
2.5 (360)
10000
22.0 (3200)
13.8 (2000)
8.1 (1200)
3.5 (510)
1.3 (190)
Density g/cm3 (lb/in3)
7.25 (0.262)
Electrical resistivity at 20°C Ω mm2/m (Ω circ. mil/ft)
1.40 (842)
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
1200
1300
Temperature °F
212
392
572
752
932
1112
1292
1472
1652
1832
2012
2192
2372
Ct
1.00
1.00
1.01
1.01
1.01
1.02
1.02
1.02
1.03
1.03
1.03
1.03
1.04
Coefficient of thermal expansion
Temperature °C (°F)
Thermal Expansion x 10-6/K (10-6 /°F)
20 - 250 (68-482)
12.4 (6.89)
20 - 500 (68-932)
13.1 (7.28)
20 - 750 (68-1382)
13.6 (7.56)
20 - 1000 (68-1832)
14.7 (8.17)
20 - 1200 (68-2192)
15.4 (8.56)
Thermal conductivity
Temperature °C (°F)
50 (122)
600 (1112)
800 (1472)
1000 (1832)
1200 (2192)
W m-1 K-1 (Btu h-1ft-1°F-1)
11 (6.4)
21 (12.1)
23 (13.3)
27 (15.6)
29 (16.8)
Specific heat capacity
Temperature °C
20
200
400
600
800
1000
1200
Temperature °F
68
392
752
1112
1472
1932
2192
kJ kg-1 K-1
0.48
0.56
0.64
0.71
0.67
0.69
0.70
Btu lb-1 °F-1
0.11
0.13
0.15
0.17
0.16
0.16
0.17
Melting point °C (°F)
1500 (2732)
Magnetic properties
The material is magnetic up to approximately 600°C (1112°F) (Curie point).
Emissivity - fully oxidized material
0.70
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®.