ASTM A556 Superheater Steel Tube

ASTM A556 / A556M – 96(2012) Standard Specification for Seamless Cold-Drawn Carbon Steel Feedwater Heater Tubes

ASTM A556 is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
1.1 This specification2 covers minimum-wall-thickness, seamless cold-drawn carbon steel tubes including bending into the form of U-tubes, if specified, for use in tubular feedwater heaters.
1.2 The tubing sizes covered shall be 5/8 to 11/4-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].
1.3 Optional supplementary requirements are provided, and when desired, shall be stated in the order.
1.4 The values stated in either inch-pound units or SI units are to be regarded separately as the standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.

Related Standard: ASTM A556,
Related Material: SA556Gr.B2, SA556Gr.C2

Outside Diameter: 12-40mm
Wall Thickness: 1-4mm
Length: max length 27 meters

Method: Cold Drawn
Delivery Condition: NBK, Bright, U bending.

Chemistry Composition

Grade C % Si % Mn % P % S %
B2 0.27 max 0.10 min 0.29-0.93 0.030 max 0.030 max
C2 0.30 max 0.10 min 0.29-1.06 0.030 max 0.030 max

Mechanical Properties

Grade Tensile Strength MPa Yield Strength MPa Hardness HRB
B2 410 min 260 min 79 min
C2 480 min 280 min 89 min

Sunny Steel superheater and reheater tubes can be delivered in sizes and lengths according to below.

Outside diameter (OD)

  • 12 to 260 mm (0.472 to 10.24 in.)

Wall thickness (WT)

  • 2-20 mm (0.0787-0.787 in.)


Tolerances according to specification or according to agreement. Standard tolerances are:

Hot finished OD +/- 1% WT +/-12.5%
Cold finished OD +/-0.75% WT +/-10%


Sandvik superheater and reheater tubes can be delivered in lengths up to 16 meters.