HAYNES® 556® alloy exhibits good resistance to both air and combustion gas oxidizing environments, and can be used for long-term exposure at temperatures up to 2000°F (1095°C). For exposures of short duration, 556 alloy can be used at higher temperatures. |
Comparative Oxidation Resistance in Flowing Air* |
| |
1800°F (980°C) - 1008 Hours |
2000°F (1095°C) - 1008 Hours |
| |
Metal Loss |
Average Metal
Affected** |
Metal Loss |
Average Metal
Affected |
| Material |
Mils |
μm |
Mils |
μm |
Mils |
μm |
Mils |
μm |
|
| X alloy |
0.3 |
8 |
0.9 |
25 |
1.5 |
40 |
2.7 |
70 |
| 556® alloy |
0.4 |
10 |
1.1 |
30 |
1.0 |
25 |
2.6 |
65 |
| alloy 601 |
0.5 |
15 |
1.3 |
35 |
1.2 |
30 |
2.6 |
65 |
| alloy 800H |
0.9 |
25 |
1.8 |
45 |
5.4 |
135 |
7.4 |
190 |
| 446 SS |
1.3 |
35 |
2.3 |
60 |
13.1 |
335 |
14.5 |
370 |
| 316 SS |
12.4 |
315 |
14.3 |
365 |
>69.0 |
>1750 |
Consumed |
Samples cycled to room temperature once-a-week
* Flowing air at a velocity of 7.0 feet/minute (212.0 cm/minute) past the samples.
** Metal Loss + Average Internal Penetration. |
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|
Metallographic Technique used for Evaluating Environmental Tests |
 |
|
Comparative Oxidation in Flowing Air 1800°F (980°C) for 1008 Hours |
| Microstructures shown are for coupons exposed for 1008 hours at 1800°F (980°C) in air flowing 7.0 feet/minute (212.0 cm/minute) past the samples. Samples were descaled by cathodically charging the coupons while they were immersed in a molten salt solution. The black area shown at the top of each picture represents actual metal loss due to oxidation. The data clearly show HAYNES 556 alloy to be superior to both RA330® alloy and Type 304 stainless steel as well as the other iron-base alloys shown in the table on the previous page. |
HAYNES® 556® alloy
Average Metal Affected =
1.1 mils (20 μm) |
RA330 alloy
Average Metal Affected =
4.3 mils (110 μm) |
Type 304 Stainless Steel
Average Metal Affected =
8.1 mils (205 μm) |
|
|
Comparative Burner Rig Oxidation Resistance 1000 Hour Exposure at 1800°F (980°C) |
| |
Metal Loss |
Average Metal
Affected* |
| Material |
Mils |
μm |
Mils |
μm |
|
| 230® alloy |
0.8 |
0.02 |
3.5 |
0.09 |
| 556® alloy |
1.7 |
0.04 |
6.2 |
0.16 |
| RA330 alloy |
7.8 |
0.20 |
11.8 |
0.30 |
| MULTIMET® alloy |
11.8 |
0.30 |
14.8 |
0.38 |
| alloy 800H |
12.3 |
0.31 |
15.3 |
0.39 |
| Type 310 Stainless Steel |
13.7 |
0.35 |
16.5 |
0.42 |
| alloy 600 |
12.3 |
0.31 |
17.8** |
0.45** |
| alloy 601 |
3.0 |
0.08 |
20.0 |
0.51 |
| |
|
|
|
|
*Metal Loss + Maximum Internal Penetration
**Extrapolated from 917 hours |
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Oxidation Test Parameters
Burner rig oxidation tests were conducted by exposing, in a rotating holder, samples 0.375 inch x 2.5 inches x thickness (9.5mm x 64mm x thickness) to the products of combustion of fuel oil (2 parts No. 1 and 1 part No. 2) 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 less than 500°F (260°C) and then reinserted into the flame tunnel. |
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