This specification covers carbon steel plates intended primarily for service in welded pressure vessels where improved notch toughness is important. According to different strength levels, the plates are available in four grades: Grades 55, 60, 65, and 70. The maximum thickness of plates is limited only by the capacity of the composition to meet the specified mechanical property requirements. The steel shall be killed and shall conform to fine austenitic grain size requirements. The mechanical properties such as tensile strength, yield strength, and elongation shall be determined by a tension test for the plates.

1.1 This specification covers carbon steel plates intended primarily for service in welded pressure vessels where improved notch toughness is important.

1.2 Plates under this specification are available in four grades having different strength levels as follows: