What is the heat treatment for ASTM A516 plates?

ASTM A516 specification is for making pressure vessels (such as oil tanks), material in carbon steel for moderate and lower temperature services, it will improve the notch toughness of the steel during the welding work.

ASTM A516 Heat Treatment
ASTM A516 plates in thickness of 40 mm [1.5 in] or under it normally supplied in as-rolled condition. In case require normalized or stress relieved shall be informed before the order.
ASTM A516 plates over 40 mm [1.5 in] thickness shall be normalized.

In case notch-toughness tests are required on plates 1.5 in [40 mm] and under this thickness, the plates shall be normalized unless otherwise specified by the purchaser.
Agreed by purchaser, cooling rates faster than cooling in air are permissible for improvement of the toughness, provided the plates are subsequently tempered in 1100 to 1300℉ [595 to 705 ℃].

ASTM A516 carbon steel plates are supplied with thickness up to150 mm.