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ASTM
A447/A447M-11(2021)
Standard Specification for Steel Castings, Chromium-Nickel-Iron Alloy (25-12 Class), for High-Temperature Service
2021
4
ASTM Vol.01.02 (2023)
This specification covers iron-base, heat-resisting alloy castings of the 25 % chromium, 12 % nickel class, intended for structural elements, containers, and supports in electric furnaces, petroleum still tube supports, and for similar applications up to 2000 °F [1095 °C].
In the absence of significant proportions of elements other than those prescribed in Section 5, the two types of alloys covered by this specification may in general be distinguished as follows:
Type I—Alloys characterized by relatively low limiting creep stress at temperatures between 1500 and 2000 °F [815 and 1095 °C], and relatively high ductility at ordinary temperatures after aging for short periods at temperatures between 1300 and 1500 °F [705 and 815 °C].
Type II—Alloys having relatively high limiting creep stress but which may develop low ductility at ordinary temperatures when aged for short periods at temperatures between 1350 and 1500 °F [730 and 815 °C].
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