High-Temperature Superheated Steam Coiled Tube for Single-Skin Furnace Applications
Product Overview
The High-Temperature Superheated Steam Coiled Tube is a specialized stainless steel coiled tube product engineered for demanding high-temperature service environments, particularly within single-skin furnaces (一段炉) operating with superheated steam. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd., this coiled tube is designed to withstand extreme thermal cycling, oxidative degradation, and mechanical stress associated with industrial process furnaces used in hydrogen production, ammonia synthesis, and other high-temperature chemical processes.
Based on extensive failure analysis of coiled tube damage in superheated steam environments, this product incorporates enhanced metallurgical design and manufacturing practices to mitigate common failure modes including oxide scale spalling, intergranular corrosion, creep rupture, and thermal fatigue cracking.
Material & Properties
The coiled tube is fabricated from high-performance austenitic stainless steels selected for superior high-temperature oxidation resistance, thermal stability, and mechanical integrity under prolonged exposure to superheated steam conditions.
- Primary Grade: SA-213 TP310 / TP310S (UNS S31008 / S31009) — Chromium-Nickel austenitic stainless steel with elevated chromium (24–26%) and nickel (19–22%) content for maximum oxidation resistance up to 1150°C.
- Alternative Grades: SA-213 TP309 (UNS S30908), SA-213 TP347H (UNS S34709), or custom superalloy compositions per customer specification.
- High-Temperature Strength: Maintains ≥60% of room-temperature tensile strength at 1000°C.
- Oxidation Resistance: Resistant to scale formation in superheated steam environments up to 1100°C continuous service temperature.
- Thermal Conductivity: 25–30 W/(m·K) at operating temperature, ensuring efficient heat transfer while maintaining structural integrity.
- Creep Resistance: Sustained stress rupture life exceeding 50,000 hours at design temperature and pressure conditions.
Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Outer Diameter (OD) | 19 mm – 114 mm (custom available) | ASME SA-213 / GB/T 14976 |
| Wall Thickness | 1.5 mm – 6.0 mm | ASME SA-213 / EN 10216-5 |
| Coil Inner Diameter (CID) | 500 mm – 2000 mm | Custom per furnace design |
| Tube Length per Coil | 10 m – 60 m (continuous) | — | Maximum Service Temperature | 1100°C (continuous) / 1150°C (intermittent) | ASTM A213 |
| Design Pressure | Up to 4.0 MPa (G) | ASME B31.3 / GB 150 |
| Surface Finish | Mirror polish (Ra ≤ 0.4 μm) or industrial finish (Ra ≤ 1.6 μm) | GB/T 8162 |
| End Condition | Plain end, beveled end, or welded couplings | ASME SA-213 |
| Heat Treatment | Solution annealed at 1050–1100°C followed by water quench | ASTM A213 |
| Applicable Standards | ASME SA-213, EN 10216-5, GB/T 14976, GB/T 14975 | — |
Manufacturing Process
The production of high-temperature superheated steam coiled tubes follows a rigorous multi-stage manufacturing process designed to ensure metallurgical homogeneity, dimensional accuracy, and long-term service reliability:
- Raw Material Selection: Vacuum Arc Remelted (VAR) or Electro Slag Remelted (ESR) ingots are selected to minimize impurity content and ensure uniform grain structure. Incoming material undergoes spectroscopic verification (PMI) to confirm chemical composition compliance.
- Hot Rolling / Extrusion: Billets are heated to forging temperature and hot-rolled or extruded into seamless tube blanks. Controlled rolling schedules ensure proper grain flow alignment for enhanced creep resistance.
- Pilgering / Mandrel Drawing: Tubes are cold-worked through pilger mills or mandrel drawing stations to achieve precise outer diameter and wall thickness tolerances (±0.1 mm).
- Solution Annealing: Continuous annealing furnaces heat tubes to 1050–1100°C followed by rapid water quenching to dissolve carbides, eliminate residual stresses, and restore full austenitic structure.
- Coil Forming: Precision coil bending machines form straight tubes into helical coils with controlled bend radii and uniform pitch, ensuring no work hardening or plastic deformation at bend regions.
- Surface Treatment: Mechanical polishing or chemical passivation is applied to remove oxide scale, achieving the required surface finish for optimal heat transfer and corrosion resistance.
- Final Inspection: Each coil undergoes hydrostatic testing, dimensional verification, and non-destructive examination (NDT) including eddy current testing and ultrasonic testing (UT).
Applications
This high-temperature coiled tube product is specifically engineered for the following industrial applications:
- Single-Skin Furnace Superheated Steam Systems: Primary application in catalytic reforming furnaces and hydrogen production units where superheated steam is circulated through coiled tubes at temperatures exceeding 900°C.
- Ammonia Synthesis Plants: Steam superheater coils in shift converters and ammonia loop systems.
- Petrochemical Processing: Steam cracking furnaces and hydroprocessing units requiring high-temperature heat exchange coils.
- Gas Turbine Balance of Plant: Feed water heaters and exhaust gas recovery systems.
- Industrial Boilers: High-pressure superheater elements in utility and process boilers operating above 550°C.
- Specialty Chemical Production: Processes involving high-temperature steam contact with reactive media.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality management systems and holds the following certifications ensuring product reliability and compliance with international standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ASME "S" Stamp — Boiler and Pressure Vessel Code compliance
- EN 10204 3.1 — Third-party inspection and material certification
- API 5CT / API 5L — Where applicable for related product lines
- PED (EU 2014/68/EU) — Pressure Equipment Directive conformity
- Material Test Reports (MTR) — Full chemical analysis, mechanical test data, and heat treatment records provided with each shipment
- NACE MR0175 / ISO 15156 — Resistance to sulfide stress cracking (for applicable grades)
Unique Selling Points
Engineered from Failure Analysis: This product design incorporates lessons learned from documented failure investigations of high-temperature coiled tubes in single-skin furnace environments, including root cause analysis of oxide scale spalling, intergranular attack, and thermal fatigue cracking. Enhanced chromium and nickel content, optimized grain structure, and controlled cooling rates directly address these failure mechanisms.
- Extended Service Life: Metallurgical optimization delivers 30–50% longer replacement intervals compared to standard grade coiled tubes under equivalent service conditions.
- Thermal Fatigue Resistance: Improved low-cycle fatigue performance accommodates frequent start-stop cycles and load variations inherent in process furnace operations.
- Custom Coil Configuration: Tailored coil pitch, diameter, and length to match specific furnace geometry and heat transfer requirements.
- Full Traceability: Each coil is traceable from raw material heat number through final inspection, enabling complete lifecycle documentation.
- Technical Support: Dedicated engineering team provides application-specific selection guidance, failure analysis consultation, and preventive maintenance recommendations.
Failure Prevention Design Features
Addressing the specific damage modes identified in superheated steam coiled tube service:
| Failure Mode | Preventive Design Feature |
|---|---|
| Oxide Scale Spalling | Elevated Cr₂O₃ scale adhesion through controlled cooling rate and Cr/Ni ratio optimization |
| Intergranular Corrosion | Ultra-low carbon (≤0.03% C) or stabilized grades (Ti/Cb addition) to prevent chromium carbide precipitation |
| Creep Rupture | Grain boundary strengthening via boron addition and optimized annealing schedule |
| Thermal Fatigue Cracking | Enhanced low-cycle fatigue resistance through solution-treated microstructure with fine equiaxed grains |
| Carburization | Chromium-rich surface layer maintained by proper heat treatment and carbon control |
Wenzhou Jixing Metal Materials Co., Ltd. is committed to delivering premium-grade high-temperature coiled tube solutions that maximize operational uptime, minimize unplanned shutdowns, and ensure long-term reliability in the most demanding industrial furnace environments.