This standard is issued under the fixed designation A 522/A 522M; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses in dicates the year of last reapproval. A superscript epsion indicates an editorial change since the last revison or reapproval.

1.Scope
1.1 This specification covers 8 and 9 % nickel-alloy steel forged or rolled flanges, fittings, valves, and parts intended for use in welded pressure vessels for low-temperature service. The specification is applicable to forgings with maximum section thickness of 3 in. [75 mm] in the double normalized and tempered condition and 5 in [125 mm] in the quenched and tempered condition. Forgings under this specification are intended for service at operation tempera-tures not lower than －320⒌[-196∩] for Type I or -275⒌[-170∩] for Type II or higher than 250⒌[121∩].
1.2 Material under this specification is acailable in two types having different chemical compositions as follows:

1.3 Supplementary requirements S1 and S2 are optional and shall apply when specified by the purchaser.
1.4 This specification is experessed in both inch-pound units and SI units However, unless the order specifies the applicable "M" specification designation (S1 units), the material shall be furnished to inch-pound units.
1.5 The values stated in either inch-pound units or S1 units are to be regarded separatily as standard. Within the text, the S1 units are shown in brackets. The values stated in each system are not exact equivalent; therefor, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specifiacation.