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Oxidation Resistance

HAYNES® 188 alloy exhibits very good resistance to both air and combustion gas oxidizing environments, and can be used for long-term continuous exposure at temperatures up to 2000°F (1095°C). For exposures of short duration, 188 alloy can be used at higher temperatures.

188 oxidation figure

Comparative Oxidation Resistance in Flowing Air, 1008 Hours

Alloy 1800°F (980°C) 2000°F (1095°C) 2100°F (1150°C)
Average Metal Affected** Metal Loss Average Metal Affected** Metal Loss Average Metal Affected** Metal Loss
mils μm mils μm mils μm mils μm mils μm mils μm
188 1.1 28 0.1 3 3.7 94 0.5 13 10.7 272 8.6 218
230® 1.5 38 0.2 5 3.3 84 0.5 13 4.4 112 1.2 30
X 1.5 38 0.2 5 4.4 112 1.3 33 6.1 115 3.6 91
625 1.9 48 0.4 10 7.8 198 3.5 89 20.2 513 18.3 465
617 2.0 51 0.3 8 3.8 97 0.6 15 5.2 132 1.0 25

*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.
**Metal Loss + Average Internal Penetration

Oxidation Test Parameters

Burner rig oxidation tests were conducted by exposing sampIes 3/8 in. x 2.5 in. x thickness (9 mm x 64 mm x thickness), in a rotating holder, to products of combustion of No. 2 fuel oil burned at a ratio of air to fuel of about 50:1. (Gas velocity was about 0.3 mach). Samples were automatically removed from the gas stream every 30 minutes and fan-cooled to near ambient temperature and then reinserted into the flame tunnel.

Comparative Burner Rig Oxidation Resistance 1000 Hour Exposure at 1800°F (980°C)

1000 Hour Exposure at 1800°F (980°C), 30 Minute Cycles
Alloy Metal Loss Average Metal Affected Maximum Metal Affected
mils μm mils μm mils μm
188 1.1 28 3.2 81 3.9 99
230® 2.8 71 5.6 142 6.4 163
617 2.4 61 5.7 145 6.9 175
625 3.7 94 6.0 152 6.6 168
X 4.3 109 7.3 185 8.0 203

Comparative Burner Rig Oxidation Resistance at 2000ºF (1095ºC) for 500 Hours

500 Hour Exposure at 2000°F (1095°C), 30 Minute Cycles
Alloy Average Metal Loss Per Side Average Metal Affected Maximum Metal Affected
mils μm mils μm mils μm
230® 7.1 180 9.9 251 11.8 300
188 10.9 277 13.1 333 14.1 358
X 11.6 295 14.0 356 15.1 384
617 13.3 338 20.9 531 21.2 538
625 Consumed

188 comparative burner rig
*625 was consumed

Water Vapor Oxidation Data

Air + 20% H2O at 1800°F (982°C), 1008 hours, cycled weekly
Alloy Metal Loss Average Metal Affected
mils μm mils μm
214® 0.04 1 0.64 16
230® 0.19 5 1.59 40
625 0.36 9 1.66 42
188 0.18  5  1.48 38
X 0.27 7 1.77 45
617 0.39 10 1.99 50
556® 0.35 9 1.85 47
HR‐120® 0.38 10 2.08 53
800HT 2.47 63 5.07 129
HR‐160® 0.77 20 5.57 141
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