885 °F (475 °C) Embrittlement
Description of Damage 885 °F (475 °C) embrittlement is a loss of ductility and fracture toughness due to a metallurgical change that can occur in stainless steels containing a ferrite phase as the result of exposure in the temperature range 600 °F to 1000 °F (315 °C to 540 °C).
The embrittlement can lead to cracking failure. 3.1.2 a) Affected Materials 400 series SS (e.g. 405, 409, 410, 410S, 430, and 446). b) c) Duplex stainless steels such as Alloys 2205, 2304, and 2507.
Austenitic (300 series) stainless steel weld metals, which normally contain up to about 10 % ferrite phase to prevent hot cracking during welding. 3.1.3 a) Critical Factors The alloy composition, particularly chromium content, amount of ferrite phase, and operating temperature are critical factors.
The lower-chromium alloys (e.g. 405, 409, 410, and 410S) are less susceptible to embrittlement. The higher chromium ferritic stainless steels [e.g. 430 (16 % to 18 % Cr) and 446 (23 % to 27 % Cr)] and duplex stainless steels (22 % to 25 % Cr) are much more susceptible.
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