Stainless Steel Coil Tube — Per-Meter Pricing Specification (Custom Length Retail)
Product Overview
The Stainless Steel Coil Tube (盘管 / Coil Tube) is a continuous-length tubular product supplied in coiled form, designed for flexible downstream processing, cutting, and fabrication. This specification addresses the per-meter unit pricing model (按米单价), which is the standard commercial pricing approach for small-batch and custom-length retail orders. The pricing is expressed in CNY per meter (元/米) and includes a proportional allocation for cutting losses (切割损耗分摊), ensuring transparent and equitable cost accounting for the end user.
Coil tubes are manufactured from high-grade austenitic stainless steel and are wound into compact coils for efficient storage, transportation, and on-demand cutting. Unlike fixed-length (定尺) pipe products, coil tubes allow customers to order precise lengths tailored to their specific fabrication requirements, minimizing material waste and optimizing inventory management.
Material & Properties
Coil tubes are predominantly produced from Austenitic Stainless Steel grades conforming to international standards including ASTM (American Society for Testing and Materials), EN (European Norms), and GB (GuoBiao — Chinese National Standard).
- Common Grades: 304 (UNS S30400), 304L (UNS S30403), 316 (UNS S31600), 316L (UNS S31603), 321 (UNS S32100), 310S (UNS S31008)
- Corrosion Resistance: Excellent resistance to atmospheric, chemical, and food-grade corrosion environments
- Mechanical Properties: High tensile strength, good formability, and weldability
- Surface Finish: Available in No.1 (annealed), 2B (cold-rolled), BA (Bright Annealed), HL (Hairline), and Mirror (8K) finishes
- Temperature Range: Suitable for cryogenic to elevated temperature applications (up to 870°C for 304, 815°C for 316)
Specifications
| Parameter | Specification | Unit | Standard / Reference |
|---|---|---|---|
| Outer Diameter (OD) | 3.0 – 168.3 | mm | ASTM A554 / GB/T 12771 |
| Wall Thickness (WT) | 0.25 – 3.00 | mm | ASTM A554 / GB/T 12771 | Coil Width (for flat/rectangular) | 10 – 150 | mm | Custom | Coil Length (Total) | 50 – 500+ | m | Depends on OD & WT | Coil ID (Inner Diameter of Coil) | 150 / 200 / 300 / 500 | mm | Custom | Tolerance on OD | ±0.1 mm or ±2% | — | ASTM A554 |
| Tolerance on WT | ±10% | — | ASTM A554 |
| Surface Finish | No.1, 2B, BA, HL, Mirror | — | ASTM A480 |
| End Condition | Plain / Beveled / Threaded | — | Custom |
| Heat Treatment | Full Annealing / Solution Annealing | — | ASTM A554 |
| Testing | Hydrostatic / Eddy Current / PMI | — | ASTM A554 / EN 10217 |
Pricing Model — Per-Meter Unit Pricing
The per-meter pricing model (按米单价) is the designated commercial approach for small-batch and custom-length retail orders (小批量、定尺零售订单). The pricing structure is defined as follows:
- Unit of Measure: CNY per meter (元/米)
- Cutting Loss Allocation (切割损耗分摊): The per-meter unit price includes a proportional surcharge to cover material losses incurred during precision cutting operations. This ensures that the quoted price reflects the true cost of delivering the requested length without additional surcharges.
- Minimum Order Quantity (MOQ): Typically applicable for orders below standard coil quantities, enabling procurement flexibility for prototype, maintenance, and specialized fabrication projects.
- Applicability: This pricing model is specifically suited for retail-level transactions, small production runs, and projects requiring non-standard dimensions.
Note: Bulk coil orders (整卷采购) are typically priced on a per-ton or per-coil basis. The per-meter model is reserved for orders where the total length is insufficient to justify full-coil procurement.
Manufacturing Process
- Coil Milling: Stainless steel strip or plate is fed into a coil mill and cold-rolled into seamless or welded tube form.
- Forming & Welding: For welded (ERW — Electric Resistance Welded) coil tubes, the formed strip is welded along the seam using high-frequency resistance welding. Seamless tubes are produced via pilger or continuous tube drawing.
- Heat Treatment: The formed tube undergoes full annealing or solution annealing in a controlled atmosphere furnace to relieve residual stresses, restore austenitic microstructure, and achieve desired mechanical properties.
- Pickling & Passivation: The tube surface is cleaned via acid pickling to remove mill scale and oxide layers, followed by passivation to enhance corrosion resistance.
- Surface Finishing: Mechanical polishing or chemical bright annealing is applied to achieve the specified surface finish grade.
- Quality Inspection: Each coil undergoes dimensional verification, hydrostatic pressure testing, eddy current flaw detection, and Positive Material Identification (PMI) verification.
- Coiling & Packaging: The inspected tube is wound into coils of specified inner diameter and packaged with protective wrapping, moisture barriers, and wooden or steel packing cases for shipment.
- Precision Cutting (for per-meter orders): Upon receipt of a custom-length order, the coil is uncoiled and cut to the specified length using a precision cutting machine (saw or shearing), with cutting losses factored into the per-meter pricing.
Applications
Stainless steel coil tubes are widely employed across multiple industries due to their combination of corrosion resistance, formability, and dimensional flexibility:
- Food & Beverage Processing: Hygienic piping, heat exchangers, and sanitary equipment (304/316L grades)
- Pharmaceutical & Biotechnology: Clean-in-place (CIP) systems, reactor piping, and fluid transfer lines
- Chemical Processing: Corrosive fluid transport, reactor coils, and heat exchanger tubes
- Automotive & Aerospace: Exhaust systems, fuel lines, and structural tubing
- Construction & Architecture: Decorative railings, handrails, and structural framing
- Energy & Power: Boiler tubes, heat exchanger coils, and solar thermal systems
- Medical Equipment: Surgical instruments, medical gas piping, and diagnostic equipment housings
Unique Selling Points
- Flexible Length Ordering: Customers can order any precise length from a single coil, eliminating the need to purchase and store full coils — ideal for small-batch production and prototype development.
- Transparent Per-Meter Pricing: The inclusion of cutting loss allocation in the per-meter price ensures no hidden surcharges, providing clear cost predictability.
- Minimal Material Waste: By ordering only the required length, customers significantly reduce material waste compared to purchasing standard fixed-length pipes.
- Multi-Grade Availability: Comprehensive range of stainless steel grades (304, 304L, 316, 316L, 321, 310S, and specialty alloys) available from a single supplier.
- Custom Surface Finishes: From industrial matte to high-gloss mirror finishes, all available within the same product platform.
- Quality Assurance: Every coil is accompanied by a full Mill Test Certificate (MTC) conforming to EN 10204 Type 3.1, with PMI verification of chemical composition.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and holds the following certifications and compliances:
- ISO 9001:2015 — Quality Management System Certification
- EN 10204 Type 3.1 — Mill Test Certificate for chemical composition, mechanical properties, and dimensional verification
- ASTM A554 — Standard Specification for Stainless Steel Tubes for General Application
- GB/T 12771 — Chinese National Standard for Welded Stainless Steel Tubes for Fluid Transport
- EN 10217-7 — European Standard for Non-Alloy and Alloy Steel Tubes for Pressure Purposes
- CE Marking — Conformity with European Directive requirements
- Hygienic Certification: Available upon request for food-grade and pharmaceutical applications (compliant with 3-A Sanitary Standards and FDA 21 CFR)
- Positive Material Identification (PMI): All shipments are verified via XRF or OES analysis to confirm grade authenticity
Ordering & Delivery Information
For per-meter pricing orders, customers should specify the following parameters when placing an inquiry:
- Stainless steel grade (e.g., 304, 316L)
- Outer diameter (OD) and wall thickness (WT)
- Required length per piece (in meters or millimeters)
- Quantity (number of pieces)
- Surface finish requirement
- End condition (plain, beveled, or threaded)
- Any additional testing or certification requirements
Orders are processed under the per-meter pricing model with cutting loss allocation included in the unit price. Lead times vary depending on stock availability, grade, and specification complexity. Custom-coiled orders with non-standard dimensions may require additional manufacturing lead time.