Stainless Steel Coil Tube – Water-Based Drawing Process (Ref. No. 1630)
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. represents a next-generation product line distinguished by its innovative water-based drawing process — a technology that replaces the traditional sand-based lubricant used in cold drawing operations. This eco-friendly manufacturing methodology eliminates the use of abrasive silica sand as a drawing agent, substituting it with a precision-engineered water-based lubricant system. The result is a high-purity, surface-integrity-optimized coil tube suitable for demanding industrial applications where contamination control is critical.
Coil tubes are continuously wound into helical coils following the cold-drawing or cold-rolling process, offering advantages in storage density, transportation efficiency, and downstream processing flexibility compared to straight-length tubing. Wenzhou Jixing Metal Materials Co., Ltd. specializes in producing these coil tubes to exact dimensional tolerances and surface finish requirements.
Material & Properties
Material Grades
- 304 / 304L – Austenitic stainless steel (UNS S30400 / S30403), offering excellent general corrosion resistance and formability
- 316 / 316L – Molybdenum-bearing austenitic stainless steel (UNS S31600 / S31603), providing superior resistance to pitting and crevice corrosion in chloride environments
- 321 – Stabilized austenitic grade (UNS S32100) with titanium stabilization for enhanced resistance to intergranular corrosion
- 304D / 316D – Deep-drawing optimized variants with tailored mechanical properties for tube-forming operations
Key Mechanical Properties (Typical, Annealed Condition)
| Property | 304 / 304L | 316 / 316L | 321 |
|---|---|---|---|
| Tensile Strength (MPa) | ≥ 520 | ≥ 515 | ≥ 515 |
| Yield Strength (0.2% Offset, MPa) | ≥ 205 | ≥ 170 | ≥ 170 |
| Elongation (% at Break) | ≥ 40 | ≥ 40 | ≥ 40 |
| Hardness (HB, Max) | 217 | 217 | 217 |
| Density (g/cm³) | 8.00 | 8.00 | 8.00 |
| Operating Temperature Range (°C) | −196 to +870 | −196 to +870 | −196 to +900 |
Chemical Composition (Typical, wt%)
| Element | 304 | 316 | 321 |
|---|---|---|---|
| C (Carbon) | ≤ 0.08 | ≤ 0.08 | ≤ 0.08 |
| Cr (Chromium) | 18.0 – 20.0 | 16.0 – 18.0 | 17.0 – 19.0 |
| Ni (Nickel) | 8.0 – 10.0 | 10.0 – 14.0 | 9.0 – 13.0 |
| Mo (Molybdenum) | — | 2.0 – 3.0 | — |
| Ti (Titanium) | — | — | 5 × (C × 1.5) – 0.70 |
| Si (Silicon) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Mn (Manganese) | ≤ 2.00 | ≤ 2.00 | ≤ 2.00 |
Specifications
| Parameter | Specification |
|---|---|
| Product Reference No. | 1630 |
| Product Form | Coil Tube (Coiltube) — continuously wound helical coil |
| Outer Diameter (OD) Range | Φ 3.0 mm – Φ 50.8 mm (adjustable per order) |
| Wall Thickness (WT) Range | 0.3 mm – 3.0 mm |
| OD Tolerance | ± 0.05 mm (precision grade); ± 0.1 mm (standard grade) |
| Wall Thickness Tolerance | ± 10% of nominal |
| Roundness | ≤ 0.1 mm (precision grade) |
| Surface Finish | No. 4 Brushed / Mirror Polished (Ra ≤ 0.4 μm) / Matte / Pickled & Passivated |
| Surface Roughness (Ra) | 0.2 – 0.8 μm (depending on finish grade) |
| Coil Inner Diameter (ID) | Φ 200 mm / Φ 300 mm / Φ 500 mm (standard options) |
| Coil Length per Roll | Up to 500 m (continuous) |
| Heat Treatment Condition | Annealed (Solution Annealed at 1050°C – 1100°C, followed by controlled cooling) |
| Standards Compliance | ASTM A269, ASTM A213, ASME SA-213, EN 10216-5, JIS G3446 |
| Drawing Lubricant | Water-based lubricant (replaces traditional silica sand) |
| Manufacturing Origin | Wenzhou, Zhejiang Province, P.R. China |
Manufacturing Process
The manufacturing of Wenzhou Jixing Metal Materials Co., Ltd. stainless steel coil tubes employs a multi-stage cold-forming process with the distinctive application of water-based drawing technology as a core differentiator. The following outlines the principal process flow:
- Raw Material Preparation: High-purity stainless steel strip (coil) is procured from certified mills, undergoes incoming inspection (chemical analysis via OES, mechanical testing, surface examination), and is slit to the required width for tube forming.
- Tube Forming (Welding & Weld-Beating): The strip is roll-formed into a tubular blank and longitudinally welded using TIG (Tungsten Inert Gas) or laser welding technology. The weld seam is subsequently flattened (weld-beating) to achieve uniform wall thickness and circular cross-section.
-
Water-Based Cold Drawing (Core Innovation):
The traditional cold drawing process utilizes silica sand or calcium-based lubricants packed inside the tube to provide internal support and reduce friction during die drawing. Wenzhou Jixing Metal Materials Co., Ltd. has adopted a water-based lubricant system that replaces sand entirely. This process involves injecting a specially formulated water-soluble lubricant into the tube bore, which serves as both a hydrostatic support medium and a low-friction drawing agent. The tube is then pulled through a precision tungsten carbide (WC) die to achieve the target OD and WT dimensions.
- Advantage 1 – Surface Integrity: Elimination of sand particles prevents micro-abrasion and embedded contaminants on the internal surface, yielding superior internal surface finish (Ra ≤ 0.4 μm achievable).
- Advantage 2 – Environmental Compliance: Water-based lubricants are non-toxic, biodegradable, and recyclable, significantly reducing environmental impact compared to sand-based processes. No silica dust exposure hazards for operators.
- Advantage 3 – Dimensional Accuracy: Hydrostatic pressure from the water-based medium provides uniform radial support, reducing ovality and improving roundness consistency across the entire coil length.
- Advantage 4 – Production Efficiency: Reduced cleaning time post-drawing, as no residual sand removal is required. Continuous flow allows for higher throughput rates.
- Advantage 5 – Product Purity: Critical for food-grade, pharmaceutical, and semiconductor applications where particulate contamination is unacceptable.
- Heat Treatment (Solution Annealing): The drawn coil tube undergoes solution annealing in a continuous belt furnace or batch annealing furnace at 1050°C – 1100°C in a protective atmosphere (hydrogen or vacuum) to relieve cold-work stresses, restore full austenitic microstructure, and achieve maximum corrosion resistance.
- Pickling & Passivation: Post-annealing oxide scale is removed via controlled acid pickling (nitric-hydrofluoric acid blend or citric acid for eco-friendly variants), followed by passivation treatment to establish a stable chromium oxide passive film on the surface.
- Surface Finishing: Depending on the customer specification, the tube may undergo mechanical polishing (mirror finish), electropolishing, or brushing to achieve the required surface quality.
- Coiling & Packaging: The finished tube is coiled onto precision-mandrel reels, wrapped with protective film, and packed in wooden or steel crates with desiccant for moisture protection during transit.
Applications
The water-based drawing process coil tube finds extensive application across industries where surface cleanliness, dimensional precision, and corrosion resistance are paramount:
- Food & Beverage Industry: Milk processing lines, brewing equipment, dairy pipelines, sanitary-grade transfer tubing — the absence of sand contamination ensures food safety compliance.
- Pharmaceutical & Biotechnology: CIP (Clean-in-Place) systems, fermentation vessel connections, bioreactor tubing, pharmaceutical fluid transfer — meets cGMP and FDA requirements.
- Semiconductor Manufacturing: Ultra-pure chemical delivery lines, ultrapure water (UPW) systems, wafer processing equipment — the superior internal surface finish minimizes particle generation.
- Chemical & Petrochemical: Process piping, heat exchanger tubes, reactor internals — 316L grade offers resistance to aggressive chemical environments.
- Medical Devices: Endoscopy tubing, surgical instrument shafts, dialysis equipment — biocompatible surface finish and cleanability.
- Automotive & Aerospace: Fuel lines, exhaust system components, hydraulic tubing, fuel cell components.
- Oil & Gas: Downhole instrumentation tubing, wellhead connections, subsea equipment.
- General Industrial: Hydraulic systems, pneumatic lines, conveyor components, spring wire applications, decorative and architectural uses.
Unique Selling Points
- Eco-Friendly Innovation: The water-based drawing process represents a significant advancement over conventional sand-drawing technology, aligning with global sustainability and environmental protection standards.
- Superior Internal Surface Quality: Elimination of abrasive sand particles results in internal surface roughness as low as Ra 0.2 μm, critical for high-purity fluid transport applications.
- Zero Particulate Contamination: The process inherently prevents silica and metal oxide particle entrapment within the tube bore, ensuring product purity.
- Enhanced Dimensional Consistency: Hydrostatic support during drawing yields superior roundness and wall thickness uniformity along the entire coil length.
- Occupational Health & Safety: Elimination of silica dust exposure eliminates silicosis risk for production workers, meeting OSHA and EU occupational health regulations.
- Cost-Effective at Scale: Reduced post-processing cleaning operations and higher throughput rates contribute to competitive pricing without compromising quality.
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality assurance systems to ensure product conformity:
- ISO 900