ASTM A213 Grade T9 Alloy Steel Seamless Tube Heat Exchange Tube
ASTM A213 Grade T9 is a classic medium-chromium alloy steel with a long history of use in high-temperature and high-pressure industries. It strikes an excellent balance between high-temperature strength, oxidation resistance, and cost, making it a key material for the manufacture of power plant boiler superheater tubes and petrochemical furnace tubes. Although replaced in some applications by newer steel grades like T91, which offer superior performance, T9 remains widely used in many existing equipment and design conditions.
Comparison with Other Common Grades
Comparison with T5 (5Cr-0.5Mo): T9's higher chromium and molybdenum content improves its high-temperature strength and oxidation resistance compared to T5.
Comparison with T11 (1.25Cr-0.5Mo) / T22 (2.25Cr-1.0Mo): T9's chromium content is significantly higher than that of T11 and T22, resulting in improved oxidation and corrosion resistance, but also a higher cost.
Compared to T91 (9Cr-1Mo-V-Nb): T91 is a modern, improved version of T9 that incorporates vanadium (V) and niobium (Nb). Through precipitation strengthening, its high-temperature strength is far superior to that of traditional T9. It is currently one of the preferred materials for supercritical and ultra-supercritical power plants. T9 can be considered the predecessor of T91.
Chemical Composition (wt %) of ASTM A213 T9 Alloy Steel Seamless Tubes
| C, % | Mn, % | P, % | S, % | Si, % | Cr, % | Mo, % |
| 0.15 max | 0.30-0.60 | 0.025 max | 0.025 max | 0.25-1.00 | 8.0-10.0 | 0.90-1.10 |
Mechanical Properties of ASTM A213 T9 Tubes
The mechanical strength of ASTM A213 Gr T9 Seamless Tubes makes them suitable for demanding service:
| Property | Value (Minimum, unless stated) |
| Tensile Strength | 60,000 psi (415 MPa) |
| Yield Strength | 30,000 psi (205 MPa) |
| Elongation (in 2in/50mm) | 30% |
| Hardness | Rockwell B: 85 max / Brinell: 179 ma |
Heat Treatment Requirements of A213 T9 Alloy Steel Seamless Tubes
| | T5, T9, T11, T22 and T91 | | |
| Grade | Heat Treatment Type | Normalizing Temperature Range F [C] | Subcritical Annealing
or Tempering
Temperature Range F
[C] |
| T5 (b,c) | Full or Isothermal Anneal | | |
| | Normalize and Temper | ***** | 1250 [675] |
| | Subcritical Anneal (T5c only) | ***** | 1325 - 1375 [715 - 745] |
| T9 | Full or Isothermal Anneal | | |
| | Normalize and Temper | ***** | 1250 [675] |
| T11 | Full or Isothermal Anneal | | |
| | Normalize and Temper | ***** | 1200 [650] |
| T22 | Full or Isothermal Anneal | | |
| | Normalize and Temper | ***** | 1250 [675] |
| T91 | Normalize and Temper | 1900-1975 [1040 - 1080] | 1350-1470 [730 - 800] |
| | Quench and Temper | 1900-1975 [1040 - 1080] | 1350-1470 [730 - 800] |
Application
1. Power plant boilers (fossil fuel power plants, combined heat and power plants)
Superheaters
Reheaters
Evaporator tubes/water walls
2. Petrochemical industry
Various process furnaces and heat exchangers also require high-temperature and high-pressure resistant piping.
Furnace tubes
Heat exchanger tubes
Industrial boilers
Pressure piping
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ASTM A213 Grade T9 Alloy Steel Seamless Tube Heat Exchange Tube Images
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