Boiler Tube
ASME SA-556M Grade C2 Seamless Cold-Drawn Tubes
SA-556M C2 is a pearlescent carbon steel used for tubular water heater in ASME SA-556m standard, which is divided into straight tubes and tubes which are required to be bent into “U” shape.
SA-556M C2 is close to 20MnG and 25MnG in GB5310 in China. It is mainly used for manufacturing 300, 600MW and other high-pressure heaters. In China, the annual demand of SA-556M C2 steel tubes are about 10000 tons.
Manufacture: Seamless process
Outer diameter: 12.7mm-38.1mm
Wall thickness: 0.5mm-3.0mm
Ends: Plain End, Beveled End, Threaded
Chemical composition of SA-556M Grade C2 steel tubes
| Grade | C | Si | Mn | P | S |
| SA-556M C2 | ≤0.30 | ≥0.10 | 0.29-1.06 | ≤0.035 | ≤0.035 |
Mechanical properties of SA-556M Grade C2 steel tubes
| Mechanical properties | Grade C2 |
| Tensile strength, min, ksi [MPa] | 70 [480] |
| Yield strength, min, ksi [MPa] | 40 [280] |
| Elongation in 2 in. or 50 mm, min, % (longitudinal) | 30 |
| Hardness | HR B 89 |
Manufacture
SA-556M Grade C2 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].