ASTM A213 Stainless Steel Coil Tube for High-Temperature Pressure Vessels
Product Overview
ASTM A213 Stainless Steel Coil Tube (盘管 Coiltube) is a precision-engineered seamless tube product specifically designed for high-temperature pressure-bearing applications in boiler systems, superheaters, and heat exchangers. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this coil tube conforms to the stringent requirements of the American Society for Testing and Materials (ASTM) A213 specification, which governs seamless austenitic and ferritic stainless steel alloy tubes used in boiler, superheater, and heat exchanger applications.
The ASTM A213 standard is the globally recognized benchmark for stainless steel tubing subjected to elevated temperatures and internal pressures. The coil tube configuration provides exceptional flexibility in fabrication and installation, making it ideal for complex geometries encountered in power generation, petrochemical processing, and industrial heat transfer systems.
Material & Properties
Material Grades
ASTM A213 covers a comprehensive range of stainless steel alloy grades, including but not limited to:
- Type 304 (UNS S30400) — General-purpose austenitic stainless steel with excellent corrosion resistance
- Type 316 (UNS S31600) — Molybdenum-enhanced austenitic grade for superior pitting and crevice corrosion resistance
- Type 310 / 310S (UNS S31000 / S31008) — High-chromium austenitic grade for extreme oxidation resistance at elevated temperatures
- Type 321 (UNS S32100) — Titanium-stabilized austenitic grade resistant to intergranular corrosion
- Type 347 (UNS S34700) — Niobium-stabilized austenitic grade for high-temperature structural integrity
Key Mechanical Properties
- High-Temperature Tensile Strength — Maintains adequate tensile strength at operating temperatures up to 1100°C (2012°F), ensuring structural integrity under sustained thermal stress
- Creep Resistance — Demonstrates excellent resistance to time-dependent deformation under prolonged high-temperature loading conditions
- Oxidation Resistance — Forms a stable, self-healing chromium oxide (Cr₂O₃) scale that protects the base metal from further oxidation in oxidizing atmospheres
- Thermal Fatigue Resistance — Withstands repeated thermal cycling without significant degradation of mechanical properties
Microstructural Requirements
- Grain Size (晶粒度) — ASTM A213 mandates a minimum grain size of ASTM No. 6 (as-rolled) or ASTM No. 8 (solution-annealed), ensuring fine-grained microstructure for optimal mechanical properties and fatigue resistance
- Decarburization Layer (脱碳层) — Maximum permissible decarburization depth is limited to 0.02 mm (0.001 inch) for grades requiring carbon control, preventing embrittlement at grain boundaries and ensuring consistent mechanical performance
- Segregation Limits — Macroscopic and microscopic segregation shall not exceed Grade 1 as defined by ASTM E102
Specifications
| Parameter | Specification / Requirement | Test Standard |
|---|---|---|
| Product Standard | ASTM A213 / A213M | — |
| Tube Type | Seamless Coil Tube (盘管) | — |
| Outside Diameter (OD) | 6.0 mm – 168.3 mm (0.236" – 6.625") | ASTM A213 Table 1 |
| Wall Thickness | 0.5 mm – 12.7 mm (0.020" – 0.500") | ASTM A213 Table 2 |
| OD Tolerance | ±0.15 mm (±0.006") for OD ≤ 13.0 mm; ±1.5% for OD > 13.0 mm | ASTM A213 §9.1 |
| Wall Thickness Tolerance | ±10% of specified thickness | ASTM A213 §9.2 |
| Grain Size | Minimum ASTM No. 6 (as-rolled); Minimum ASTM No. 8 (annealed) | ASTM E112 |
| Decarburization | Not to exceed 0.02 mm (0.001 inch) maximum depth | ASTM E102 |
| High-Temperature Tensile Strength | Per ASTM A213 Table 3 at specified temperature | ASTM A388 |
| Coil Weight | Up to 5,000 kg (11,000 lbs) per coil | — |
| Surface Finish | Mill finish, polished, or custom per customer specification | — |
| Heat Treatment | Solution annealing (1040°C – 1150°C, followed by rapid cooling) | ASTM A213 §10 |
Manufacturing Process
The production of ASTM A213 stainless steel coil tube follows a rigorous, multi-stage manufacturing process to ensure compliance with all dimensional, metallurgical, and mechanical requirements:
- Raw Material Preparation — High-purity stainless steel billets or slabs are produced via Vacuum Arc Remelting (VAR) or Electro-Slag Remelting (ESR) to ensure low impurity levels and controlled composition.
- Piercing — Hot-rolled billets are pierced at temperatures between 1150°C and 1250°C to form hollow blanks, establishing the initial internal diameter.
- Hot Rolling — The pierced blanks undergo multi-stand hot rolling to achieve the target outer diameter and wall thickness within specified tolerances.
- Pipe Making (Cross Rolling / Roll Piercing) — Precision cross-rolling processes refine the tube geometry and achieve the final seamless configuration.
- Coil Forming — The seamless tubes are cold-bent into coil configuration using CNC-controlled bending equipment, ensuring uniform curvature and no material deformation or cracking.
- Solution Annealing — Tubes are solution-annealed at temperatures between 1040°C and 1150°C followed by rapid water quenching to dissolve carbides, refine grain structure, and restore full austenitic properties.
- Pickling and Passivation — Surface scale is removed via acid pickling (HNO₃/HF or citric acid), followed by passivation to restore the protective chromium oxide layer.
- Quality Inspection — Comprehensive testing including hydrostatic pressure testing, dimensional measurement, ultrasonic testing (UT), and metallurgical examination.
Applications
ASTM A213 stainless steel coil tubes manufactured by Wenzhou Jixing Metal Materials Co., Ltd are deployed in demanding industrial environments where high-temperature performance, corrosion resistance, and mechanical reliability are paramount:
- Boiler Systems — Water-wall tubes, economizer tubes, and drum connections in utility boilers operating at temperatures up to 600°C (1112°F)
- Superheaters and Reheaters — High-temperature steam superheater tubes in fossil-fuel and nuclear power plants, withstanding temperatures up to 1100°C (2012°F)
- Heat Exchangers — Shell-and-tube heat exchangers in petrochemical, chemical processing, and oil refining industries
- Power Generation — Steam turbine feedwater heaters, condensers, and auxiliary heat recovery systems
- Chemical Processing — Reaction vessel internals, distillation columns, and process heat transfer loops
- Food and Pharmaceutical Industry — Steam sterilization systems and sanitary heat exchangers requiring high purity and corrosion resistance
Quality Certifications & Testing
Every coil tube product is manufactured and inspected in strict accordance with the following quality assurance protocols:
- Hydrostatic Testing — Each tube is hydrostatically tested at a pressure of at least 55 MPa (8000 psi) or 1.5 times the calculated hoop stress, per ASTM A213 §12.1
- Ultrasonic Testing (UT) — Full-length ultrasonic examination to detect internal defects such as laminations, inclusions, and voids, per ASTM A777
- Mechanical Testing — Tensile testing at room temperature and elevated temperatures to verify compliance with specified mechanical properties
- Metallographic Examination — Grain size determination per ASTM E112 and decarburization assessment per ASTM E102
- Chemical Analysis — Spectrometric analysis to confirm composition within ASTM A213 specified ranges for all alloying elements
- Dimensional Inspection — 100% inspection of OD, wall thickness, straightness, and coil configuration
Unique Selling Points
- Comprehensive ASTM A213 Compliance — Full adherence to the internationally recognized ASTM A213 standard ensures seamless integration into global engineering projects
- Superior High-Temperature Performance — Engineered for sustained operation at extreme temperatures with proven creep resistance and oxidation resistance
- Precision Coil Configuration — CNC-controlled coil forming eliminates stress concentrations and ensures uniform curvature, reducing installation time and labor costs
- Stringent Microstructural Control — Rigorous grain size and decarburization limits guarantee consistent mechanical properties throughout the tube's service life
- Wide Grade Selection — Availability across multiple ASTM A213 alloy grades allows engineers to optimize material selection for specific service conditions
- End-to-End Traceability — Complete mill test certificates (MTC) and heat traceability documentation accompany every shipment
Note: All products are manufactured to meet or exceed the requirements specified in ASTM A213 / A213M. Custom specifications and non-standard dimensions are available upon request. Wenzhou Jixing Metal Materials Co., Ltd maintains ISO 9001:2015 quality management system certification and provides full third-party inspection (TPI) support for critical applications.