ASTM A203/ A203, is the standard specification covers nickel-alloy steel paltes intended primarily for welded pressure vessels. These nickel alloy steels are mainly used for moderate- or low-temperature services. The nickel content added imparts significant improvements in fracture toughness and fatigue resistance of the steel.
Plates under this specification are available with four strength levels and two nickel compositions: Grade A, Grade B, Grade D, Grade E and Grade F. The maximum thickness of plates is limited only by the capacity of the composition to meet the specified mechanical property requirements. In engineering practice, Grade A and B are usually referred to as “2% nickel steel“; Grade D, E & F are usually referred to as “3% nickel steel“.
|ASTM A203 Nickel-Alloy Steel Plates|
|Element||Gr. A||Gr. B||Gr. D||Gr. E & F|
|2"< t ≤4"||0.20||0.24||0.20||0.23|
|ASTM A203||Grade A & D||Grade B & E||Grade F|
The ASTM A203 steel shall be killed and shall conform to the fine grain size requirement of specification ASTM A20/ A20M. All plates of Grade A, B, D, and E shall be normalized except that approved by the purchaser for Grade A, B, D and E, cooling rates faster than air cooling are permissible for improvement of the toughness, provided the plates sre subsequently tempered at not less than 1100°F [595°C] for not less than 0.5 hours. All plates of Grade F shall be heat treated by heating into the austenitic range, quenching in water, and tempering at not less than 1100°F [595°C] for not less than 0.5 hours.
The inspection and testing required for ASTM A203 nickel-alloy steel plates include: chemical analysis, tension test, Charpy V-Notch impact test, drop weight test, high-temperature tension test, ultrasonic examination, as well as magnetic particle examination.