ASTM A556 Grade B2 Seamless Cold-Drawn Feedwater Heater Tube
ASTM A556 Grade B2 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].
Description
ASTM A556 Grade B2 Seamless Cold-Drawn Feedwater Heater Tubes
Standard Specification for Seamless Cold-Drawn Carbon Steel Feedwater Heater Tubes
ASTM A556 Grade B2 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 B2 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 B2 | |
| Carbon, max | 0.27 |
| Manganese | 0.29–0.93 |
| Phosphorus, max | 0.035 |
| Sulfur, max | 0.035 |
| Silicon, min | 0.10 |
Mechanical Properties
| Grade B2 | |
| Tensile strength, min, ksi [MPa] | 60 [410] |
| Yield strength, min, ksi [MPa] | 37 [260] |
|
Elongation in 2 in. or 50 mm, min, % (longitudinal)
|
30 |
| Hardness | HR B 79 |
Tolerances of ASTM A556 Grade B2 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