ASTM A522 / A522M

This specification2 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 operating temperatures not lower than −320 °F [−196 °C] for Type I or −275 °F [−170 °C] for Type II or higher than 250 °F [121 °C]. Material under this specification is available in two types having different chemical compositions as follows: Type I and Nominal Nickel Content, % is 9,Type II and Nominal Nickel Content, % is 8. This specification is expressed in both inch-pound units and SI units. However, unless the order specifies the applicable “M” specification designation (SI units), the material shall be furnished to inch-pound units.

Chemical Properties

Type	Carbon, max	Manganese, max	Phosphorus, max	Sulphur, max	SiliconA	Nickel
I	0.13	0.90	0.025 max	0.025 max	0.15 - 0.30	8.5 - 9.5
II	0.13	0.90	0.025 max	0.025 max	0.15 - 0.30	7.5 - 8.5

Note : A When vacuum carbon deoxidation is used, the maximum silicon content shall be 0.10 %.

Mechanical Properties

Tensile strength, min, ksi [MPa]	Yield strength, min, (0.2 % off-set), ksi [MPa]	Elongation in 2 in. [50mm], min, %	Reduction of area, min, %
100 [690]	75 [515]	22	45