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

Comparative Dynamic Oxidation

Burner rig oxidation tests were conducted by exposing samples of 3/8” x 2.5” x thickness (9mm x 64 mm x thickness), in a rotating holder to the products of combustion of 2 parts No. 1 and 1 part No. 2 fuel 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 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)

Water Vapor Testing

Amount of metal affected for high‐temperature sheet (0.060 ‐ 0.125”) alloys exposed for 360 days (8,640 h) in flowing air.

*Metal loss was calculated from final and initial metal thicknesses; i.e. ML = (OMT – FMT) /2

Static Oxidation Comparison