HAYNES^® 230^® alloy exhibits excellent resistance to both air and combustion gas oxidizing environments, and can be used for long-term continuous exposure at temperatures up to 2100°F (1150°C). For exposures of short duration, 230 alloy can be used at higher temperatures.

Schematic Representation of Metallographic Technique used for Evaluating Oxidation Tests

1. Metal Loss = (A-B)/2
2. Average Internal Penetration = C
3. Maximum Internal Penetration = D
4. Average Metal Affected = ((A-B)/2) + C
5. Maximum Metal Affected = ((A-B)/2) + D

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

Oxidation Test Parameters
Burner rig oxidation tests were conducted by exposing samples 3/8 inch x 2.5 inches x thickness (9 mm x 64 mm x thickness), in a rotating holder, to the 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 500 Hour Exposure at 2000°F (1093°C) (Width of Micros Indicates Original Sample Thickness)

230 alloy Average Metal Affected = 5.2 Mils (132 µm)/Side	Alloy 600 Average Metal Affected = 19.5 Mils (495 µm)/Side	Type 310 Stainless Steel Average Metal Affected = 23.7 Mils (602 µm)/Side
HASTELLOY X alloy Average Metal Affected = 12.9 Mils (328 µm)/Side	RA330 Alloy Average Metal Affected = 12.9 Mils (328 µm)/Side	INCONEL alloy 601 Average Metal Affected = > 24.0 Mils (610 µm)/Side

Comparative Oxidation Resistance in Flowing Air*

Comparative Oxidation in Flowing Air 2100°F (1150°C) for 1008 Hours

Microstructures shown are for coupons exposed for 1008 hours at 2100°F (1150°C) in air flowing 7.0 feet/minute (2.1 m/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 230 alloy to be superior to both INCONEL alloy 601 and alloy 800H, as well as the other heat-resistant materials listed in the table above.

                              230 alloy
                              Average Metal Affected
                              = 3.4 mils (86 µm)

                            INCONEL alloy 601
                            Average Metal Affected
                            = 5.3 mils (135 µm)

                            Alloy 800H
                            Average Metal Affected
                            = 8.9 mils (226 µm)

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HAYNES® 230® alloy Information

Schematic Representation of Metallographic Technique used for Evaluating Oxidation Tests

HAYNES^® 230^® alloy Information