ASTM A541/A541M-05(2010)

1.1 This specification covers requirements for quenched and tempered carbon and alloy steel forgings for pressure vessel components.

1.2 All grades are considered weldable under proper conditions. Welding technique is of fundamental importance, and it is presupposed that welding procedure and inspection will be in accordance with approved methods for the grade of material used.

Note 1 - Grades 1 and 1A have different chemistries but the same mechanical requirements.