What SA213 T9 is
T9 is a 9Cr-1Mo ferritic alloy steel. The high chromium content resists sulfidic and oxidizing attack at radiant-section temperatures, and it handles high-temperature hydrogen further along the Nelson curve than T5 or T22. It should not be confused with T91, the modified 9Cr-1Mo-V grade used for supercritical boilers, which has different chemistry, heat treatment, and welding requirements.
Chemical composition
| Element | Requirement |
|---|---|
| Carbon | 0.15% max |
| Manganese | 0.30 to 0.60% |
| Silicon | 0.25 to 1.00% |
| Chromium | 8.00 to 10.00% |
| Molybdenum | 0.90 to 1.10% |
| Phosphorus / Sulfur | 0.025% max each |
Mechanical properties
| Property | Minimum |
|---|---|
| Tensile strength | 60,000 psi (415 MPa) |
| Yield strength | 30,000 psi (205 MPa) |
| Elongation in 2" | 30% |
| Hardness | 85 HRB max |
Where it is used
- Radiant section tubes in crude, vacuum, and coker heaters.
- Hydrogen reformer and hydrotreater service.
- High-temperature sulfur and H2S exchangers.
- Superheater and reheater tube in industrial boilers burning high-sulfur fuel.
One order, the whole ladder
Refinery heater retubes rarely need one grade. Ameritube quotes T5, T9, T11, T22, and the stainless grades from a single desk, with matching MTR formats and one inspection release.
OD, minimum wall, length, quantity, heat treatment, hardness cap, PMI, and the customer or licensor specification. State whether T9 or T91 is intended, they are not interchangeable.