Oxidation Resistance

Comparative Oxidation Resistance in Flowing Air

Material 1600°F (871°C) 1800°F (982°C)
Average Metal Loss Average Metal Affected Average Metal Loss Average Metal Affected
Mils μm Mils μm Mils μm Mils μm
HR-224® 0 0 0.2 5 0 0 0.3 8
214® 0 0 0.3 8 0 0 0.5 13
230® 0 0 0.9 23 0.2 5 1.6 41
625 0.1 3 0.6 15 0.2 5 1.9 48
X 0.1 3 1 25 0.3 8 1.9 48
HR-120® 0.1 3 1.1 28 0.3 8 2.0 51
601 - - - - 0.4 10 1.7 43
800HT 0.1 3 1 25 0.5 13 4.1 104
347 SS 0.3 8 0.7 18 - - - -
253 MA 0.2 5 0.9 23 1.3 33 3.0 76

Flowing air at a velocity of 7.0 ft/min (213.4 cm/min) past the samples. Samples cycled to room temperature once per week.

Comparative Long-Term Oxidation Resistance

Material 1800°F (982°C)
Average Metal Loss Average Metal Affected
Mils μm Mils μm
HR-224® 0.1 3 0.1 3
214® 0.1 3 0.5 13
230® 0.1 3 2.7 69
X 0.2 5 2.8 71
HR-120® 0.5 13 3.3 84
625 2.6 66 8.6 218

Alloys exposed for 360 days (8,640 h) in flowing air, cycled once per month.

Comparative Oxidation Resistance in Water Vapor

Material 1400°F (760°C) 1600°F (871°C)
Average Metal Loss Average Metal Affected Average Metal Loss Average Metal Affected
Mils μm Mils μm Mils μm Mils μm
HR-224® 0.05 1 0.25 7 0.06 2 0.26 7
214® 0.02 1 0.22 7 0.05 1 0.35 9
230® 0.09 2 1.19 30 0.21 5 1.91 49
HR-120® 0.12 3 0.72 18 0.26 7 2.06 52

Amount of metal affected for high‐temperature sheet (0.125”) alloys exposed for 8640h (cycled monthly) in air + 10%H2O

Comparative Cyclic Oxidation

Material 1400°F (760°C) 1600°F (871°C) 1800°F (982°C) 2000°F (1093°C)
Average Metal Loss Average Metal Affected Average Metal Loss Average Metal Affected Average Metal Loss Average Metal Affected Average Metal Loss Average Metal Affected
Mils μm Mils μm Mils μm Mils μm Mils μm Mils μm Mils μm Mils μm
HR-224® < 0.1 0.6 0.1 1.9 0.1 3 0.3 8 0.1 3 0.3 8 0.2 5 0.8 20
214® < 0.1 0.3 0.1 1.6 0.1 3 0.1 3 0.1 3 0.5 13 0.1 6 0.4 10
230® < 0.1 0.8 0.1 2.7 0.1 3 0.7 18 0.2 5 1.1 28 0.9 23 4.1 104
X - - - - 0.2 5 1.0 25 0.3 8 1.6 41 10 254 12.1 307
601 - - - - - - - - 0.5 13 1.9 48 - - - -
625 - - - - 0.1 3 0.5 13 0.4 10 2.0 51 - - - -
HR-120® < 0.1 1.2 0.2 6.0 0.2 5 0.9 23 0.4 10 2.0 51 18.5 470 20.6 523
600 - - - - 0.1 3 0.8 20 0.5 13 2.2 56 - - - -
800HT - - - - 0.3 8 1.3 33 8 203 9.8 249 30.8 782 32.2 818

Amount of metal affected for alloys exposed to flowing air for 1000-h, cycled 1x/10h

Schematic Representation of Metallographic Technique used for Evaluating Oxidation

HR-224 oxidation schematic

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