Stainless Steel Coil Tube (Coiltube) — Horizontal Pumping Grade
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) is a continuously wound, seamless stainless steel tube supplied in coil form, engineered for high-pressure pumping applications, structural piping systems, and industrial fluid conveyance. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd, this coil tube product line is specifically designed to withstand extreme pumping pressures and long-distance horizontal transport scenarios, drawing upon advanced metallurgical engineering principles validated through rigorous pumping experiments including C70 self-consolidating concrete (Self-Consolidating Concrete, SCC) horizontal coil pipe pumping trials at distances exceeding 1,590 meters.
Coil tubes offer significant logistical and installation advantages over straight-length pipe segments, including reduced joint count, lower labor costs, and superior flexibility in routing configurations. The coil form factor eliminates the need for field welding at frequent intervals, thereby minimizing points of failure and enhancing system integrity in demanding operational environments.
2. Material Composition & Mechanical Properties
2.1 Base Material Grades
- AISI 304 (UNS S30408) — General-purpose austenitic stainless steel with excellent corrosion resistance and formability
- AISI 316 (UNS S31608) — Molybdenum-enhanced austenitic grade for elevated chemical and pitting corrosion resistance
- AISI 321 (UNS S32108) — Titanium-stabilized grade for high-temperature service and resistance to intergranular corrosion
- AISI 316L (UNS S31603) — Low-carbon variant of 316 for superior weldability and resistance to sensitization
2.2 Key Mechanical Properties
- Tensile Strength (Ultimate Tensile Strength, UTS): ≥ 520 MPa (AISI 304/316); ≥ 550 MPa (AISI 321)
- Yield Strength (0.2% Proof Stress): ≥ 205 MPa (AISI 304); ≥ 240 MPa (AISI 316)
- Elongation at Break: ≥ 40% (minimum, per ASTM A213/A269)
- Hardness (Rockwell B): ≤ 95 HRB (annealed condition)
- Operating Temperature Range: −196 °C to +870 °C (depending on grade)
- Maximum Pumping Pressure Capability: ≥ 60 MPa (subject to wall thickness and diameter)
3. Technical Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 6.35 mm – 114.3 mm (¼" – 4½") | ASTM A269 / GB/T 14976 |
| Wall Thickness (WT) | 0.5 mm – 8.0 mm (±0.1 mm tolerance) | ASTM A213 / EN 10216-5 |
| Coil Inner Diameter (CID) | 300 mm – 1,200 mm | Manufacturer Specification |
| Coil Length per Spool | 50 m – 500 m (customizable) | — |
| Surface Finish | 2B (Cold-Rolled Annealed), No. 4 Brushed, Electropolished, or Mirror (Ra ≤ 0.4 μm) | ASTM A480 / GB/T 4237 |
| End Form | Plain cut, Beveled, Threaded (NPT/BSP), or Flanged | ASME B1.20.1 / EN 10226 |
| Welding Method (Seam) | Automatic Orbital TIG (Tungsten Inert Gas) Welding with Back-Purging | ASTM A213 / AWS D10.9 |
| Maximum Pumping Distance (Horizontal) | Up to 1,590 m (validated via SCC pumping trials) | Experimental Validation |
| Maximum Pumping Pressure | Up to 60 MPa (grade- and geometry-dependent) | ASME B31.3 |
| Dimensional Tolerance | ±0.15 mm (OD); ±10% (WT) | ASTM A213 / GB/T 14976 |
| Corrosion Resistance | Potential Pit Resistance Index (PPRI) ≥ 24 (304); ≥ 31 (316) | ASTM G48 |
| Hydrostatic Test Pressure | 2.5 × Maximum Working Pressure (MWP) | ASME B31.3 |
4. Manufacturing Process
4.1 Production Workflow
- Raw Material Selection: Virgin stainless steel strip or cold-rolled coil sourced from certified mills (e.g., POSCO, Outokumpu, Taiyuan Stainless Steel). Each batch undergoes spectrographic verification (Optical Emission Spectrometry, OES) to confirm chemical composition compliance.
- Cutting & Forming: Precision slitting and slitting to target width, followed by roll-forming into the desired circular cross-section using multi-stand forming mills with synchronized roll adjustment.
- Welding: High-frequency induction welding or automatic orbital TIG welding with continuous argon back-purging to ensure full-penetration, oxide-free weld seams. Weld seam quality is monitored via inline ultrasonic testing (Ultrasonic Testing, UT).
- Heat Treatment: Solution annealing at 1,050–1,150 °C followed by controlled water quenching to restore full austenitic microstructure and eliminate residual stresses introduced during forming.
- Pickling & Passivation: Immersion in nitric/hydrofluoric acid blend to remove mill scale and weld discoloration, followed by passivation to establish a stable chromium oxide passive film (minimum 100 Å thickness).
- Surface Finishing: Mechanical polishing, electropolishing, or passivation to achieve the specified surface roughness (Surface Roughness, Ra) profile.
- Quality Inspection: 100% inline inspection including dimensional measurement (Laser Diameter Gauge), eddy current flaw detection (Eddy Current Testing, ECT), hydrostatic pressure testing, and visual examination of weld seams.
- Coiling & Packaging: Final coiling onto precision-wound spools with protective end caps, moisture-absorbing desiccant packs, and stretch-wrap or wooden crate packaging for shipment.
4.2 Pumping Performance Validation
The coil tube product line has been validated through extensive horizontal pumping experiments utilizing C70-grade Self-Consolidating Concrete (SCC) over distances reaching 1,590 meters. These trials demonstrated that the stainless steel coil tube maintains structural integrity, dimensional stability, and flow efficiency under sustained pumping pressures without deformation, delamination, or premature fatigue failure. The seamless coil configuration minimizes pressure drop at joints and eliminates potential leakage pathways that are common in segmented pipe installations.
5. Applications
- Concrete Pumping Systems: High-pressure horizontal and vertical pumping of self-consolidating concrete, ready-mix concrete, and specialized construction slurries
- Chemical Processing: Conveyance of corrosive acids, alkalis, solvents, and reactive chemical intermediates in petrochemical and pharmaceutical plants
- Food & Beverage Industry: Hygienic-grade fluid transfer in dairy, brewing, and pharmaceutical manufacturing (3-A Sanitary or EHEDG compliant configurations)
- Marine & Offshore: Subsea pipelines, ballast systems, and ballast water treatment conduits resistant to chloride-induced stress corrosion cracking
- Power Generation: Superheater tubes, condenser tubes, and feedwater lines in fossil-fuel and nuclear power plants
- Automotive & Aerospace: Fuel lines, exhaust system components, and hydraulic fluid circuits requiring high temperature and pressure resistance
- Construction & Civil Engineering: Rebar anchoring systems, post-tensioning ducts, and structural bracing in seismic zones
- Medical Equipment: Instrumentation tubing, endoscope sheaths, and medical gas delivery systems
6. Quality Certifications & Standards Compliance
| Certification / Standard | Description |
|---|---|
| ISO 9001:2015 | Quality Management System (Quality Management System, QMS) certification for manufacturing processes |
| ISO 14001:2015 | Environmental Management System (Environmental Management System, EMS) certification |
| ISO 45001:2018 | Occupational Health and Safety Management System (Occupational Health and Safety Management System, OHSMS) certification |
| EN 10204 3.1 | Inspection Certificate — Material Test Report (Material Test Report, MTR) with product-specific test data |
| ASTM A213 / A269 | Standard specifications for seamless and welded austenitic stainless steel tubing |
| GB/T 14976 | Chinese National Standard for cold-rolled stainless steel seamless tubes |
| GB/T 12771 | Chinese National Standard for cold-rolled stainless steel welded tubes |
| ASME B31.3 | Process Piping Code compliance for design and pressure testing |
| NACE MR0175 / ISO 15156 | Materials for use in H₂S-containing environments in oil and gas production |
| PED 2014/68/EU | EU Pressure Equipment Directive compliance (where applicable by pressure rating) |
| Mill Test Certificate (MTC) | Full chemical composition, mechanical properties, and heat treatment records for each production heat |
7. Unique Selling Points
Validated Long-Distance Pumping Performance: The coil tube has been experimentally proven to maintain structural integrity and flow efficiency during horizontal pumping of C70 self-consolidating concrete over distances exceeding 1,590 meters — a benchmark that surpasses conventional segmented pipe installations.
- Seamless Coil Configuration: Eliminates field joints, reducing potential failure points by up to 95% compared to cut-and-weld straight pipe installations, thereby enhancing system reliability and reducing maintenance frequency.
- Superior Corrosion Resistance: Chromium-nickel-molybdenum alloy composition provides exceptional resistance to pitting, crevice corrosion, and chloride-induced stress corrosion cracking in aggressive environments.
- High Formability & Weldability: Full austenitic microstructure ensures excellent cold-forming capability and resistance to sensitization during welding, enabling complex on-site routing without mechanical degradation.
- Customizable Coil Geometry: Coil inner diameter, tube dimensions, and surface finish can be tailored to specific project requirements, enabling optimized logistics and reduced material waste.
- Full Traceability: Every coil is accompanied by a comprehensive Material Test Report (MTR) with heat number, chemical analysis, mechanical test results, and non-destructive examination (Non-Destructive Examination, NDE) records ensuring complete supply chain traceability.
- Cost-Effective Installation: Reduced labor hours, fewer fittings, and lower transportation costs associated with coil delivery result in total installed cost savings of 20–35% versus conventional pipe segment procurement.
8. Ordering Information & Customization
Wenzhou Jixing Metal Materials Co., Ltd offers full customization services including: non-standard outer diameters, custom wall thicknesses, specialized surface finishes (electropolished to Ra ≤ 0.2 μm), custom coil diameters, and bespoke end configurations. Minimum order quantities (Minimum Order Quantity, MOQ) and lead times vary based on grade, dimensions, and surface specification. Technical consultation is available for project-specific engineering support, including pumping pressure calculations, flow analysis, and material selection guidance.