Product Description
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Standard:
ASTM A213 is a globally recognized standard governing seamless stainless steel and alloy steel tubes for critical high-temperature, high-pressure applications in boilers, superheaters, and heat exchangers. It specifies rigorous requirements for chemical composition, mechanical properties, heat treatment, and non-destructive testing to ensure performance in extreme environments. Compliance with this standard guarantees compatibility with ASME BPVC Section I (boilers) and Section VIII (pressure vessels).
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Dimensional Specifications:
- OD Tolerance: ±0.05 mm for precision applications, ensuring uniform fluid flow and fit in tube sheets.
- WT Tolerance: ±10% of nominal thickness, critical for maintaining pressure integrity and heat transfer efficiency.
- Straightness: ≤1.6 mm per meter (0.063 in per 3 ft) to facilitate installation in heat exchanger bundles.
- U-Bend Specifications: For U-tubes, radius ranges from 1.5×OD to 5×OD, with wall thickness reduction ≤15% post-bending.
- Performance Advantages:
- High-Temperature Stability: Austenitic grades (e.g., TP347) resist oxidation and creep at 600-650°C; ferritic-alloy T91 excels in 550-650°C steam environments.
- Corrosion Resistance: Alloying elements (Cr, Ni, Mo) protect against corrosive media (acids, salts, steam condensate), extending service life.
- Efficient Heat Transfer: Seamless construction and smooth surface minimize thermal resistance, enhancing heat exchange rates in boilers and heat exchangers.
- Formability: Excellent ductility allows bending into U-shapes, coils, or custom configurations without cracking, optimizing space in compact equipment.
- Quality Assurance:
- Testing Protocols: Mandatory hydrostatic testing at 3.45 MPa (500 psi) for 10 seconds to verify leak tightness.
- Non-Destructive Testing (NDT): Eddy current testing for surface defects; ultrasonic testing for internal flaws in critical applications.
- Mechanical Testing: Tensile, yield, and elongation tests per ASTM E8; hardness testing (Rockwell B for austenitic, Rockwell C for alloys).
- Heat Treatment: Annealing for austenitic grades to relieve stress; normalizing and tempering for alloy grades (e.g., T91) to enhance strength.
- Chemical Composition Analysis:
- Austenitic Grades (TP304): Cr (18-20%), Ni (8-10.5%), C (≤0.08%), ensuring ductility and corrosion resistance.
- Low-Carbon Variants (TP304L): C (≤0.03%) prevents carbide precipitation during welding, maintaining corrosion resistance.
- Mo-Alloyed (TP316): Mo (2-3%) enhances resistance to chloride-induced pitting, ideal for coastal or chemical environments.
- Alloy T91: Cr (8-9.5%), Mo (0.85-1.05%), V (0.18-0.25%) for high-temperature strength and creep resistance.
- Application Scenarios:
- Boilers: Water wall tubes, superheater tubes, and economizer tubes in thermal power plants.
- Heat Exchangers: Shell-and-tube exchangers in chemical processing, oil refining, and HVAC systems.
- Superheaters/Reheaters: High-temperature steam lines in power generation.
- Condensers: Cooling water tubes in marine and industrial condenser units.
- Packaging and Delivery:
- Tubes are bundled with steel straps, separated by non-abrasive material to prevent scratches.
- Ends are capped with plastic protectors to avoid contamination during transit.
- Bulk orders packed in wooden crates or steel frames; small quantities in pallets with weatherproof wrapping.
- Shipped with MTRs, certification documents, and dimensional inspection reports for traceability and customer verification.
Chemical Composition
ASTM A213 covers various grades of stainless steel, such as TP304, TP316, etc. Here are the chemical compositions of some common grades (in wt.%):
| Grade |
C |
Mn |
Si |
P |
S |
Cr |
Ni |
Mo |
N |
Other Elements |
| TP304/304L |
≤0.08 |
≤2.00 |
≤1.00 |
≤0.045 |
≤0.030 |
18.0 - 20.0 |
8.0 - 11.0 |
- |
- |
- |
| TP316/316L |
≤0.08 |
≤2.00 |
≤1.00 |
≤0.045 |
≤0.030 |
16.0 - 18.0 |
10.0 - 14.0 |
2.0 - 3.0 |
- |
- |
| TP317/317L |
≤0.08 |
≤2.00 |
≤1.00 |
≤0.045 |
≤0.030 |
18.0 - 20.0 |
11.0 - 15.0 |
3.0 - 4.0 |
- |
- |
| TP347/347H/347HFG |
≤0.08 |
≤2.00 |
≤1.00 |
≤0.045 |
≤0.030 |
17.0 - 19.0 |
9.0 - 13.0 |
- |
- |
Nb: 0.20 |
The typical mechanical properties of some common grades are as follows:
| Grade |
Tensile Strength (MPa) |
Yield Strength (MPa) |
Elongation (%) |
| TP304/304L |
≥515 |
≥205 |
≥35 |
| TP316/316L |
≥515 |
≥205 |
≥35 |
| TP317/317L |
≥515 |
≥205 |
≥35 |
| TP347/347H/347HFG |
≥515 |
≥205 |
≥35 |
| TP444 |
≥485 |
≥275 |
≥20 |
Processing of Production
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