ASTM A537 Class 1,2,3 Boiler and Pressure vessel steel plate

The ASTM A537 specification is the Standard Specification for Pressure Vessel Plates, Heat-Treated, Carbon-Manganese-Silicon Steel used in the applications of fusion welded pressure vessels and structures.   Typical applications are pressure vessels designed for moderate and lower-temperature service requiring excellent notch toughness as well as API 650 and API 620 storage tanks.  Class 1 material is available as Normalized and Class 2 is available as Quenched & Tempered plates.

ASTM A537 Class 3(A537CL3)
ASTM A537 Class 2(A537CL2)
ASTM A537 Class 1(A537CL1)
Referenced Documents

ASTM Standards:
A20/A20M: Specification for General Requirements for Pressure Vessel Plates
A435/A435: For Straight-Beam Ultrasonic Examination of Steel Plate
A577/A577M: For Ultrasonic Angle-Beam Examination of Steel Plates
A578/A578M: For Straight-Beam Ultrasonic Examination of Rolled Steel Plates for Special Applications

Manufacturing Notes:
Steel Plate under ASTM A537 Class 1, 2 and 3 shall be killed steel and comply with fine austenitic grain size requirement of Specification A20/A20M.

Heat Treatment Methods:
All plates under ASTM A537 shall be heat treated as follows:
ASTM A537 Class 1 plates shall be normalized.
Class 2 and Class 3 plates shall be quenched and tempered. The tempering temperature for Class 2 plates shall not be less than 1100°F [595°C] and not less than 1150°F [620°C] for Class 3 plates.