Stainless Steel Coil Tube — Bright Annealed Coiled Tubing (Model No. 1166)
1. Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered continuous coiled tubing product designed for industrial and commercial applications requiring high corrosion resistance, mechanical integrity, and dimensional accuracy. This product line encompasses seamless stainless steel tubes delivered in coil form, offering superior handling efficiency, minimal material waste, and enhanced downstream processing compatibility compared to straight-length alternatives.
The coil tube is produced through an advanced manufacturing pipeline that integrates automated forming, precision welding (where applicable), and a proprietary SCADA (Supervisory Control and Data Acquisition)-controlled bright annealing process. This system ensures consistent metallurgical properties and surface finish quality across the entire production length, distinguishing this product from conventional coil tubing available in the market.
2. Material & Properties
2.1 Base Material Grades
- ASTM A213 TP304 / 304L — General-purpose austenitic stainless steel with excellent corrosion resistance and formability
- ASTM A213 TP316 / 316L — Enhanced molybdenum-bearing grade for superior resistance to pitting and crevice corrosion in aggressive environments
- ASTM A213 TP321 / TP347 — Stabilized grades with titanium or niobium additions for high-temperature service applications
- ASTM A213 TP310S — High-temperature alloy grade suitable for furnace components and extreme thermal environments
2.2 Mechanical Properties (Annealed Condition)
| Property | Specification | Test Method |
|---|---|---|
| Tensile Strength (Rm) | ≥ 515 MPa (74,700 psi) | ASTM E8 / E8M |
| Yield Strength (Rp0.2) | ≥ 205 MPa (29,700 psi) | ASTM E8 / E8M |
| Elongation (A) | ≥ 40% | ASTM E8 / E8M |
| Hardness (HV) | ≤ 210 | ASTM E92 |
| Impact Energy (20°C) | ≥ 47 J (35 ft-lb) | ASTM E23 |
2.3 Chemical Composition (Typical, wt%)
| Grade | C | Cr | Ni | Mo | Si | Mn | N |
|---|---|---|---|---|---|---|---|
| 304 | ≤ 0.08 | 18.0–20.0 | 8.0–10.5 | — | ≤ 0.75 | ≤ 2.0 | ≤ 0.10 |
| 316 | ≤ 0.08 | 16.0–18.0 | 10.0–14.0 | 2.0–3.0 | ≤ 0.75 | ≤ 2.0 | ≤ 0.10 |
| 321 | ≤ 0.08 | 17.0–19.0 | 9.0–12.0 | — | ≤ 0.75 | ≤ 2.0 | ≤ 0.10 |
3. Specifications
3.1 Dimensional Parameters
| Parameter | Range / Value | Tolerance |
|---|---|---|
| Outer Diameter (OD) | 3.0 mm – 219.0 mm (1/8" – 8") | ±0.10 mm (±0.004") |
| Wall Thickness | 0.25 mm – 12.0 mm (0.010" – 0.472") | ±10% |
| Coil Length | 100 m – 2,000 m (328 ft – 6,562 ft) | ±5% |
| Coil Inner Diameter | 200 mm – 600 mm (7.87" – 23.62") | ±10 mm |
| Coil Weight | 500 kg – 5,000 kg (1,100 – 11,000 lbs) | — |
| Surface Finish | Bright Annealed (BA), Ra ≤ 0.4 μm | ASTM B436 / EN 10204 |
| End Condition | Flush-cut, burr-free | Visual inspection |
3.2 Applicable Standards
- ASTM A213 / A213M — Standard Specification for Seamless Austenitic Chromium-Stainless Steel Tubes for High-Temperature Service
- ASTM A269 / A269M — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubes for General Use
- EN 10217-7 — Technical Delivery Conditions for Stainless Steel Tubes for Pressure Purposes
- GB/T 12771 — Technical Delivery Conditions for Seamless Stainless Steel Tubes for General Purposes (Chinese National Standard)
- ISO 4326 — Heat Resistant Stainless Steel Tubes for General Purposes
- JIS G3459 — Seamless Heat-Resistant Stainless Steel Tubes (Japanese Industrial Standard)
4. Manufacturing Process
4.1 Process Flow Summary
- Raw Material Preparation — Hot-rolled stainless steel coils or billets are inspected for chemical composition (spectrometric analysis), mechanical properties, and surface condition prior to entering the production line.
- Pipe Forming — The coil is fed through precision roller dies that progressively form the flat strip into a tubular shape. For seamless variants, hot-rolling or cold-drawing methods are employed on billet stock.
- Welding (Welded Variants) — Where applicable, the formed tube is welded using TIG (Tungsten Inert Gas) or plasma welding with inert gas backing (argon) to maintain oxidation-free weld zones and ensure metallurgical homogeneity.
- Precision Sizing & Straightening — Multi-stand rolling mills adjust the outer diameter and wall thickness to final dimensions with tight tolerance control.
- Bright Annealing (SCADA-Controlled) — The coil tube passes through a bottom-rolling bright annealing furnace equipped with a SCADA system. The furnace maintains a controlled reducing atmosphere (typically nitrogen with a hydrogen dew point of ≤ −60°C) at temperatures between 1,020°C and 1,150°C to relieve residual stresses, refine grain structure, and produce a bright, oxide-free surface finish.
- Pickle & Passivate (Post-Annealing) — The tube is treated with a dilute acid solution to remove any residual surface oxides, followed by passivation to restore the protective chromium oxide layer.
- Coiling & Packaging — The finished product is wound onto precision coils with controlled tension to prevent deformation. Coils are wrapped in protective film, wooden or cardboard end caps, and secured for transport.
4.2 SCADA-Controlled Bright Annealing Furnace — Key Features
The integration of a SCADA (Supervisory Control and Data Acquisition) system in the bright annealing furnace represents a critical differentiator in this product line. The SCADA system provides:
- Real-time temperature monitoring across multiple zones of the furnace with ±5°C accuracy, ensuring uniform heat treatment
- Automated atmosphere control maintaining precise dew point and oxygen potential throughout the annealing cycle
- Continuous logging and traceability of all process parameters for quality documentation and audit compliance
- Automated speed control of the bottom-rolling mechanism to synchronize coil feed rate with thermal processing requirements
- Predictive maintenance alerts for furnace components, minimizing unplanned downtime and ensuring consistent product quality
5. Applications
| Industry | Application | Key Requirements Addressed |
|---|---|---|
| Petrochemical & Oil/Gas | Heat exchanger tubes, reactor components, piping systems | Corrosion resistance, high-temperature strength |
| Food & Beverage Processing | Sanitary piping, brewing equipment, dairy processing lines | Hygienic surface finish, non-toxicity, ease of cleaning |
| Pharmaceutical | Process piping, CIP (Clean-in-Place) systems, reactor vessels | Biocompatibility, corrosion resistance, precision dimensions |
| Aerospace | Fuel lines, hydraulic systems, exhaust components | Lightweight, high strength-to-weight ratio, fatigue resistance |
| Automotive | Exhaust systems, fuel injection lines, turbocharger components | Heat resistance, vibration resistance, long service life |
| Medical Devices | Surgical instruments, implant-compatible tubing, dialysis systems | Bio-inertness, ultra-smooth surface finish, dimensional precision |
| Energy / Solar | Concentrated solar power (CSP) receiver tubes, heat transfer systems | Thermal fatigue resistance, oxidation resistance at elevated temperatures |
| Construction & Architecture | Structural elements, decorative railings, facade systems | Aesthetic finish, corrosion resistance, formability |
6. Quality Certifications & Assurance
6.1 Manufacturer Certifications
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ISO 45001:2018 — Occupational Health and Safety Management System
- EN 10204 Type 3.1 — Inspection Certificate confirming conformity to specified standards
- Mill Test Certificates (MTC) — Provided for every production lot with full chemical and mechanical test data
6.2 Third-Party Testing & Inspection
- NDT (Non-Destructive Testing) — Eddy current testing (ECT) and ultrasonic testing (UT) performed on 100% of production length to detect internal and surface defects
- Hydrostatic Testing — Pressure testing at 1.5× the maximum operating pressure to verify weld integrity and dimensional soundness
- Spectrometric Analysis — Optical emission spectrometry (OES) for verification of chemical composition on every heat
- Surface Roughness Measurement — Verified against Ra ≤ 0.4 μm specification using contact profilometry
- Third-Party Inspection — Available upon request (SGS, Bureau Veritas, TÜV, DNV, or equivalent)
6.3 Traceability
Every coil tube production lot is assigned a unique identification number linked to the SCADA system database, enabling full traceability from raw material origin through every manufacturing stage to final delivery. This ensures rapid identification and containment in the event of any quality concern, providing customers with comprehensive supply chain transparency.
7. Unique Selling Points
1. SCADA-Integrated Bright Annealing: The use of a SCADA-controlled bottom-rolling bright annealing furnace ensures unprecedented process repeatability and surface quality consistency across the entire coil length — a capability not commonly found among standard coil tube manufacturers.
2. Precision Dimensional Control: Tolerances of ±0.10 mm on outer diameter enable seamless integration into high-precision assemblies without secondary machining.
3. Full Traceability: Digital process logging through the SCADA system provides complete manufacturing history for every coil, supporting regulatory compliance in pharmaceutical, aerospace, and food-grade applications