A 556/A 556M Grade A2 Seamless Carbon Steel Boiler Tubes for Boiler Pipe
1.Standard Scope
1.1 This specifification2 covers minimum-wall-thickness,seamless cold-drawn carbon steel tubes
including bending into the form of U-tubes, if specifified,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.
2.Manufacture
(1)Manufactur-------Tubes shall be made by the seamless process and shall be cold drawn.
(2 )Heat Treatment:
2.2.1 Cold-drawn tubes shall be heat treated after the fifinal cold-draw pass at a temperature
of 1200°F[640°C] or higher to ensure ductility satisfactory for rolling into tube sheets and tomeet
mechanical properties as specifified.
2.2.2 If stress-relief anneal of the U-bends is specifified, the anneal shall consist of heating the bent
portion within a range of 1100 to 1200°F [585 to 640°C].
3.Chemical Requirement :
| Element | Composition ,% |
| Grade A2 | Grade B2 | Grade C2 |
| Carbon, max | 0.18 | 0.27 | 0.30 |
| Manganese | 0.27-0.63 | 0.29-0.93 | 0.29-1.06 |
| Phosphorus, max | 0.035 | 0.035 | 0.035 |
| Sulfur, max | 0.035 | 0.035 | 0.035 |
| Silicon , min | ... | 0.10 | 0.10 |
4.Tensile Requirements:
| | Grade A2 | Grade B2 | Grade C2 |
| Tensile strength,min,ksi(Mpa) | 47(320) | 60(410) | 70(480) |
| Yield Strength,min,ksi(Mpa) | 26(180) | 37(260) | 40(280) |
| Elongation in 2 in or 50min, min,%(longitudinal) | 35 | 30 | 30 |
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A 556 / A 556m Grade A2 Seamless Boiler Tubes Carbon Steel Images
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