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| ブランド名: | YUHONG |
| モデル番号: | ASTM A335 P22 合金鋼シームレスベンドパイプ |
| MOQ: | 治療部位により異なります |
| パッケージの詳細: | プライウッドケース/パレット、バッグ |
| 支払条件: | LC、T/T |
ASME SA335/ ASTM A335 P22 Alloy Steel Pipe Seamless Boiler Tube Bends for Power Plant Usage
A335 P22 alloy steel seamless bend pipe are high‑strength, heat‑resistant components that require careful bending methods, tight dimensional tolerances, and mandatory post‑bend heat treatment to perform reliably in boiler service.
In a boiler, tubes are rarely straight. Bends are used to navigate tube bundles, absorb thermal expansion, and optimize heat transfer surface area. Here are the typical shapes fabricated from A335 P22 (or A213 T22 for smaller tubes):
| Shape | Description | Typical Boiler Location | Stress Concern |
| U-Bends | 180° hairpin turn | Superheater & Reheater tube bundles (floating or fixed tubesheet designs) | High residual stress on intrados (inner radius) |
| J-Bends | 90° + straight leg | Boiler drain lines or tube-to-header connections | Thinning at extrados (outer radius) |
| S-Bends (Offset Bends) | Two opposing 90° or 45° bends | Water wall panel transitions or furnace floor penetrations | Ovality & wall thinning at both bends |
| Piggott Bends (Expansion Loops) | Large radius 180° or 360° loop | Long steam lines between superheater stages | Cyclic fatigue from thermal expansion/contraction |
| Serpentine Coils | Multiple alternating U-bends | Radiant superheater panels (vertical or horizontal) | Creep & relaxation in high-temperature zones |
| Pigtail Coils | Multiple helical loops (small radius) | Smaller desuperheaters or sampling points | Thinning & cracking due to severe cold working |
Chemical Compositions of ASTM A213 / ASME SA213 T5 Alloy Steel Seamless Bend Pipe Boiler Tube
| Grade | Carbon | Manganese | Phosphorus | Sulfur | Silicon | Chromium | Molybdenum |
| P22 | 0.05-0.15 | 0.3-0.6 | 0.025 | 0.025 | 0.5 | 1.9-2.6 | 0.87-1.13 |
Mechanical Properties ASME SA335 / ASTM A335 P22 Alloy Steel Seamless Bend Pipe Boiler Tube
| Grade | Yield Strength (Mpa) | Tensile Strength (Mpa) | Elongation (%) | High-Temperature Strength |
| P22 | 0.05-0.15 | 0.3-0.6 | 0.025 | well up to 593°C (1100°F) |
Failure Risks Specific to P22 Bends
When inspecting or designing bends for boiler service, watch for these:
Reheat Cracking: Occurs in the coarse-grained HAZ of a bend that was improperly PWHTed, especially during startup/shutdown cycles.
Type IV Cracking: In welded bends longitudinal failure in the fine-grained HAZ after decades of creep service.
Graphitization: Rare in P22 but possible if incorrectly annealed below 700°C.
Thinning-induced burst: On the outer radius of tight J- or U-bends in superheater sections.
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