Oxidation Resistance

Oxidation in Air

Laboratory tests were conducted in flowing air at 1800 to 2200°F (982 to 1204°C) for 1008 hours, with specimens cycled to room temperature once every 168 hours.

Alloy 1800°F (982°C) 2000°F (1093°C) 2100°F (1149°C) 2200°F (1204°C)
Metal Loss Average Metal Affected Metal Loss Average Metal Affected Metal Loss Average Metal Affected Metal Loss Average Metal Affected
mils μm mils μm mils μm mils μm mils μm mils μm mils μm mils μm
HR-160® 0.7 18 5.5 140 1.7 43 10.3 262 2.5 64 16.0 406 3.6 91 22.0 559
800HT 0.0 0 4.1 104 7.6 193 11.6 295 11.0 279 15.0 381 19.4 493 >58 >1473
253MA 1.3 33 3.0 76 0.7 18 8.2 208 8.7 221 16.5 419 18.6 472 29.2 742
RA85H 0.5 13 8.2 208 2.9 74 25.9 658 3.7 94 >59 >1499 3.9 99 >59 >1499

Long-Term Oxidation in Air

Laboratory tests were conducted at 2000°F (1093°C) in still air (box furnace), with specimens being cycled to room temperature once every 30 days.

Alloy 1800°F (982°C) 2000°F (1093°C) 2100°F (1149°C) 2200°F (1204°C)
Metal Loss Average Metal Affected Metal Loss Average Metal Affected Metal Loss Average Metal Affected Metal Loss Average Metal Affected
mils μm mils μm mils μm mils μm mils μm mils μm mils μm mils μm
HR-160® 2.5 64 16.7 424 3.6 91 29.0 737 7.6 193 58.7 1491 16.7 4204 26.3 668
601 0.5 13 22.4 569 5.4 137 45.1 1146 12.6 320 72.8 1849 27.3 693 38.9 988
RA85H 6.3 160 53.7 1364 17.9 455 80.3 2040 20.0 508 94.8 2408 >251.7 >6393 >251.7 >6393
800HT 20.7 526 79.8 2027 44.3 1125 51.0 1295 65.2 1656 70.3 1786 >249.9 >6373 >249.9 >6373

Plate exposed for 360 days ( 8,640 hours) in still air, except for 1800°F test, which was exposed for 720 days (17,280 hours).  Cycled once per month.

Alloy 1800°F (982°C) 2000°F (1093°C) 2100°F (1149°C) 2200°F (1204°C)
Metal Loss Average Metal Affected Metal Loss Average Metal Affected Metal Loss Average Metal Affected Metal Loss Average Metal Affected
mils μm mils μm mils μm mils μm mils μm mils μm mils μm mils μm
HR-160® 1.2 30 12.0 305 2.7 69 27.9 709 5.3 135 44.6 1133 8.9 226 >250.0 >6350
601 0.0 0 2.6 66 3.4 86 10.5 267 5.3 135 14.6 371 10.3 262 23.9 607
RA85H 0.7 18 14.6 371 8.9 226 14.3 363 6.4 163 >250.0 >6350 8.4 213 >250.0 >6350
800HT 4.6 117 14.1 358 22.2 564 27.9 709 43.9 1115 48.9 1242 65.6 1666 >250.0 >6350

Plate exposed for 360 days ( 8,640 hours) in still air.  Cycled once every two months.

Metallographic Technique used for Evaluating Environmental Tests

214 environmental tests

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