Scope
1.1 This specification covers minimum-wall-thickness, seamless
cold-drawn carbon steel tubes including bending into the from of
u-tubes, if specified, for use in tubular feedwater heaters.
1.2 The tubing sizes covered shall be 5/8 to 1 2/4-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 hen
desired, shall be stated in the order.
1.4 The values stared 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 sated 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. The inch-pound
units shall apply unless the "M" designation of this specification
is specified in the order.
ASTM A556/A556M specification 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. 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].
- Manufacture: tubes shall be made by the seamless process and shall be cold
drawn.
- 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].
- Inspection & Test: tension test, flattening test, flaring test, hardness test, NDT,
surface inspection and dimension check.
- Length: 11800mm; 12000mm; 16000mm; 18000mm; 20000mm; and so on.
- Max length: 27000mm, also U bending can be offered.
ASTM A556/A556M TUBES MECHANICAL PROPERTIES
| Grade | Tensile strength, min, ksi [MPa] | Yield strength, min, ksi [MPa] | Elongation in 2 in. or 50 mm, min, % (longitudinal) | Hardness Requirements |
| A2 | 47 [320] | 26 [180] | 35 | HR B 72 |
| B2 | 60 [410] | 37 [260] | 30 | HR B 79 |
| C2 | 70 [480] | 40 [280] | 30 | HR B 89 |
ASTM A556/A556M TUBES CHEMICAL COMPOSITION
| Grade | C % | Si % | Mn % | P % | S % |
| A2 | 0.18 | ... | 0.27–0.63 | 0.035 | 0.035 |
| 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 |
ASTM A556/A556M TOLERANCES:
| Processing methods | OD | WT |
| Hot finished | +/- 1% | +/-12.5% |
| Cold finished | +/-0.75% | +/-10% |
