81
Appendix
Emissivity table (continue)
Material
Temperature
(
°C
)
Emissivity
approximation
Iron
Polished cast iron
200
0.21
Processed cast iron
20
0.44
Polished tempered
iron
40
~
250
0.28
Polished steel ingot
770
~
1040
0.52
~
0.56
Raw welded steel
945
~
1100
0.52
~
0.61
Surface ferric oxide
20
0.69
Completely rusty
surface
22
0.66
Rolled iron plate
100
0.74
Oxidized steel
198
~
600
0.64
~
0.78
Cast iron (Oxidizing at
600°C)
198
~
600
0.79
Steel (Oxidizing at
600°C )
125
~
520
0.78
~
0.82
Electrolytic ferric
oxide
500
~
1200
0.85
~
0.89
Iron plate
925
~
1120
0.87
~
0.95
Cast iron, heavy ferric
oxide
25
0.80
Tempered iron, ferric
oxide
40
~
250
0.95
Melting surface
22
0.94
Melting cast iron
1300
~
1400
0.29
Melting mild steel
1600
~
1800
0.28
Liquid steel
1500
~
1650
0.42
~
0.53
Pure liquid iron
1515
~
1680
0.42
~
0.45