ASTM A556 Grade A2 Seamless Cold-Drawn Feedwater Heater Tube
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.

Description

ASTM A556 Grade A2 Seamless Cold-Drawn Feedwater Heater Tubes

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].
Heat Treatment:
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].
Chemical Composition
Element Composition, %
Grade A2
Carbon, max 0.18
Manganese 0.27–0.63
Phosphorus, max 0.035
Sulfur, max 0.035
Silicon, min ….
Mechanical Properties
Grade A2
Tensile strength, min, ksi [MPa] 47 [320]
Yield strength, min, ksi [MPa] 26 [180]
Elongation in 2 in. or 50 mm, min, % (longitudinal)
35
Hardness HR B 72
Tolerances of ASTM A556 Grade A2 Feedwater Heater Tubes
Hot finished
OD +/- 1%
WT +/-12.5%
Cold finished
OD +/-0.75%
WT +/-10%
Mechanical Tests 
Tension Test
Flattening Test
Flaring Test
Hardness Test
Hydrostatic Test
Packaging 
Bundles (hexagonal),
Wooden Boxes,
Crates (steel/wooden)
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.