Standard Specification for Seamless Cold-Drawn Carbon Steel Feedwater Heater Tubes
ASTM A556 Grade A2 Steel Tubes covers minimum-wall-thickness,seamless cold-drawn carbon steel tubes including bending into the form of U-tubes, for use in tubular feedwater heaters.
ASTM A556 Grade A2 Seamless Cold-Drawn Feedwater Heater Tubes sizes covered shall be 5 ⁄ 8 to 1 1 ⁄ 4 -in. [15.9 to 31.8-mm] outside diameter, inclusive, with minimum wall thicknesses equal to or greater than 0.045 in. [1.1 mm].
Cold-drawn tubes shall be heat treated after the final cold-draw pass at a temperature of 1200°F [640°C] or higher to ensure ductility satisfactory for rolling into tube sheets and to meet mechanical properties as specified.
If stress-relief anneal of the U-bends is specified, the anneal shall consist of heating the bent portion within a range of 1100 to 1200°F [585 to 640°C].
Tensile strength, min, ksi [MPa]
Yield strength, min, ksi [MPa]
Elongation in 2 in. or 50 mm, min, % (longitudinal)
HR B 72
Tolerances of ASTM A556 Grade A2 Feedwater Heater Tubes
OD +/- 1%
The tubing be packaged or bundled in such a manner as to prevent damage in ordinary handling and transportation and identified by a tag with the name of the manufacturer, purchase order number, specification number and grade, and size.