Stainless Steel Coil Tube — Theoretical Weight Settlement with Agreed Tolerance Deviation
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. offers a premium range of stainless steel coil tubes (coiltubes) designed for industrial, commercial, and specialized manufacturing applications. These coil tubes are supplied in continuous coil form, enabling efficient downstream processing including straightening, cutting, forming, and welding without the need for individual length handling. The product line encompasses a broad selection of stainless steel grades, outer diameters, and wall thicknesses, all manufactured to meet stringent international standards.
The coil tube format provides significant logistical and operational advantages over straight-length tubing, reducing handling time, minimizing cut-off waste, and streamlining inventory management. Each coil is carefully wound and packaged to ensure structural integrity during transport and storage.
Material & Properties
Stainless steel coil tubes are available in multiple austenitic, ferritic, and duplex grades, each selected for specific performance requirements:
- Austenitic Grades (304, 304L, 316, 316L, 321, 310S): Superior corrosion resistance, excellent formability, and high-temperature capability. Ideal for chemical processing, food-grade, and marine environments.
- Ferritic Grades (430, 439, 444): Good resistance to stress corrosion cracking, moderate formability, and cost-effective for general applications.
- Duplex Grades (2205, 2507): Combines high strength with outstanding resistance to chloride-induced corrosion, suitable for demanding industrial and offshore environments.
- Super-Austenitic Grades (904L, AL-6XN): Exceptional resistance to aggressive chemical media and high-temperature oxidation.
Key Mechanical Properties (Typical Values for 304 Grade)
- Tensile Strength: ≥ 520 MPa (≥ 75,400 psi)
- Yield Strength: ≥ 205 MPa (≥ 29,700 psi)
- Elongation: ≥ 40% (minimum)
- Hardness: ≤ 210 HB (Brinell)
- Density: 7.93 g/cm³ (0.283 lb/in³)
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Available Grades | 304, 304L, 316, 316L, 321, 310S, 430, 444, 2205, 2507, 904L, AL-6XN |
| Outer Diameter Range | 3.0 mm – 168.3 mm (1/8" – 6-5/8") |
| Wall Thickness Range | 0.3 mm – 12.0 mm (0.012" – 0.472") |
| Surface Finish | No. 1 (Industrial), 2B, BA (Bright Annealed), Pickled & Passivated, Custom |
| Coil Weight | Typically 1,000 – 5,000 kg (2,205 – 11,023 lbs) per coil |
| Manufacturing Method | Seamless (Hot Rolled, Cold Drawn) or Welded (ERW, TIG) |
| Applicable Standards | ASTM A213, ASTM A269, ASTM A219, EN 10216-5, EN 10217-7, GB/T 14975, JIS G3459 |
| Settlement Method | Theoretical Weight with Agreed Tolerance Deviation |
| Weight Tolerance | ±1.0% – ±3.0% (negotiable per order; excess deviation settled at actual weight) |
| Delivery Condition | Annealed, Solution Treated, Cold Worked (½ Hard, Full Hard) |
| Packaging | Wooden crate or steel frame coil holder with moisture-proof wrapping |
Settlement & Pricing Methodology
Wenzhou Jixing Metal Materials Co., Ltd. employs a theoretical weight settlement with agreed tolerance deviation model for coil tube orders. This approach balances operational efficiency with commercial fairness:
- Theoretical Weight Calculation: The base settlement weight is calculated using the standard formula: Weight = π × (D − t) × t × L × ρ, where D is the outer diameter, t is the wall thickness, L is the coil length, and ρ is the material density. This ensures consistent and transparent pricing independent of minor dimensional variations inherent in coil production.
- Agreed Tolerance Deviation: A mutually agreed tolerance range (typically ±1.0% to ±3.0%) is established at the time of order confirmation. Within this range, settlement proceeds at theoretical weight, streamlining logistics and reducing administrative burden.
- Excess Deviation Adjustment: Should the actual weighed quantity exceed the agreed tolerance range, the settlement is adjusted to reflect the actual measured weight. This mechanism ensures fairness for both buyer and seller.
- Verification & Documentation: Each coil is accompanied by a weight certificate. Buyers may request independent verification through third-party inspection agencies upon delivery.
Key Advantage: This hybrid settlement method combines the speed and simplicity of theoretical weight pricing with the accountability of actual weight verification, providing a transparent, efficient, and equitable commercial framework.
Manufacturing Process
The production of stainless steel coil tubes follows a rigorous multi-stage process:
- Raw Material Selection: High-quality stainless steel billets or strip are sourced from certified mills, with each batch verified for chemical composition and mechanical properties.
- Hot Rolling / Extrusion: Billets are heated to forging temperature and passed through rollers or extruded through dies to produce seamless tube blanks.
- Piercing & Elongation: The solid billet is pierced and drawn through successive die sets to achieve the target inner diameter and wall thickness.
- Cold Drawing / Mandrel Drawing: For precision tube specifications, the hot-rolled tube is cold-drawn over a mandrel to achieve tight dimensional tolerances and improved surface finish.
- Heat Treatment: Tubes are annealed or solution-treated to relieve residual stresses, restore full austenitic microstructure, and ensure optimal corrosion resistance.
- Pickling & Passivation: Chemical treatment removes scale and oxide layers, followed by passivation to enhance the protective chromium oxide film.
- Coiling: Finished tubes are wound into coils of specified length and weight, secured with steel banding and protective end caps.
- Final Inspection: Each coil undergoes dimensional checking, surface inspection, hydrostatic pressure testing (where applicable), and chemical/spectroscopic verification.
Applications
Stainless steel coil tubes from Wenzhou Jixing Metal Materials Co., Ltd. serve a wide spectrum of industrial and commercial sectors:
- Chemical Processing: Reactor coils, heat exchanger tubes, piping systems, and reactor internals requiring resistance to aggressive chemicals and elevated temperatures.
- Food & Beverage Industry: Hygienic-grade tubing for milk processing, brewing, pharmaceutical, and food packaging equipment (304L/316L grades).
- Energy & Power Generation: Boiler tubes, superheater tubes, condenser tubes, and nuclear-grade components (321, 310S, 904L grades).
- Automotive & Aerospace: Exhaust systems, fuel lines, hydraulic tubing, and structural components requiring high strength-to-weight ratios.
- Petrochemical & Offshore: Subsea piping, oil well casing, heat exchangers, and corrosion-resistant components (2205, 2507, AL-6XN grades).
- Construction & Architecture: Structural tubing, handrails, decorative elements, and architectural facades.
- Medical & Laboratory: Surgical instrument tubing, MRI-compatible components, and laboratory equipment housings.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control.
- ISO 14001 — Environmental Management System certification demonstrating commitment to sustainable manufacturing practices.
- EN 10204 3.1 Material Test Certificates — Issued for every shipment, providing full traceability of material composition, heat number, and mechanical test results.
- NADCAP / PED (CE) Marking — Available for pressure equipment and critical industrial applications upon request.
- Mill Test Reports (MTRs): Comprehensive documentation including chemical analysis (OES), mechanical test results, and dimensional inspection reports for each coil.
- Third-Party Inspection: Products available for inspection by SGS, BV, TUV, or other accredited agencies at the point of manufacture.
Unique Selling Points
- Transparent Hybrid Settlement: The theoretical weight plus agreed tolerance deviation model eliminates pricing ambiguity while maintaining commercial fairness — a rare and customer-friendly approach in the coil tube market.
- Extensive Grade Range: From standard austenitic to advanced super-austenitic and duplex grades, covering virtually all industrial requirements from a single supplier.
- Full Traceability: Every coil is traceable from raw material heat to finished product, supported by EN 10204 3.1 certificates and digital documentation.
- Flexible Customization: Non-standard dimensions, special surface finishes, and custom coiling configurations available to meet project-specific requirements.
- Competitive Lead Times: Strategic inventory management and in-house manufacturing capability ensure reliable delivery schedules even for high-volume orders.
- Technical Support: Dedicated engineering team provides material selection guidance, specification matching, and post-delivery technical consultation.