Stainless Steel Coil Tube (Coiltube) — Product Technical Specification
1. Product Overview
The Stainless Steel Coil Tube (also referred to as Coil Tube or Coiltube) is a precision-engineered tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is supplied in continuous coil form, offering significant advantages in material utilization, processing efficiency, and downstream fabrication cost reduction. The coil tube is produced through advanced continuous forming and annealing technologies, drawing upon modern coil tube production methodologies including those referenced in Modern Copper Coil Tube Production Technology (《现代紫铜盘管生产技术》), adapted and optimized for austenitic stainless steel alloys.
Coil tubes are distinguished from standard straight-length tubes by their helical wound configuration, which allows for seamless, continuous delivery to forming lines, welding stations, and automated manufacturing systems. This format eliminates the need for butt-welding multiple straight sections, thereby reducing defect density, improving dimensional consistency, and enhancing overall product integrity.
2. Material & Properties
2.1 Base Materials
Wenzhou Jixing Metal Materials Co., Ltd. offers stainless steel coil tubes fabricated from the following primary alloy grades:
- 304 (ASTM A213 TP304) — General-purpose austenitic stainless steel with excellent corrosion resistance and formability
- 316L (ASTM A213 TP316L) — Enhanced corrosion resistance with molybdenum addition for aggressive chemical environments
- 321 (ASTM A213 TP321) — Titanium-stabilized grade suitable for elevated temperature applications
- 310S (ASTM A213 TP310S) — High-temperature creep-resistant austenitic grade
- Custom Alloy Compositions — Available upon request for specialized industrial applications
2.2 Mechanical Properties (Typical Values for Grade 304)
| Property | Specification |
|---|---|
| Tensile Strength (抗拉强度) | ≥ 515 MPa (75 ksi) |
| Yield Strength (屈服强度) | ≥ 205 MPa (30 ksi) |
| Elongation (延伸率) | ≥ 40% (in 50 mm gauge length) |
| Hardness (硬度) | ≤ 220 HV (Annealed Condition) |
| Density (密度) | 8.0 g/cm³ |
| Operating Temperature Range | −196°C to +870°C |
2.3 Chemical Composition (ASTM A213 Grade 304)
| Element | Specification (%) |
|---|---|
| Carbon (C) | ≤ 0.08 |
| Chromium (Cr) | 18.0 – 20.0 |
| Nickel (Ni) | 8.0 – 10.5 |
| Manganese (Mn) | ≤ 2.0 |
| Silicon (Si) | ≤ 0.75 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 |
3. Specifications
3.1 Dimensional Parameters
| Parameter | Range / Standard |
|---|---|
| Outer Diameter (外径) | 6.0 mm – 108.0 mm |
| Wall Thickness (壁厚) | 0.30 mm – 8.0 mm |
| Coil Width (盘管宽度) | As per customer requirement (up to 200 mm) |
| Coil Length (盘管长度) | 50 m – 500 m per coil (configurable) |
| Coil Inner Diameter (内径) | 200 mm – 600 mm |
| Dimensional Tolerance (尺寸公差) | ± 0.05 mm (OD); ± 0.03 mm (wall thickness) |
| Surface Finish (表面光洁度) | 2B, BA (Bright Annealed), or Custom Polished |
| Manufacturing Standard | ASTM A213 / A269, GB/T 14976, EN 10216-5 |
3.2 Available Grades Summary
| Grade | Key Feature | Typical Application |
|---|---|---|
| 304 / 304L | General corrosion resistance, excellent weldability | Food processing, chemical equipment, architectural |
| 316 / 316L | Superior pitting and crevice corrosion resistance | Marine, pharmaceutical, pulp & paper |
| 321 | Intergranular corrosion resistance at high temperatures | Furnace components, heat exchangers |
| 310S | High-temperature strength and oxidation resistance | Industrial furnaces, kiln elements |
4. Manufacturing Process
The production of stainless steel coil tubes at Wenzhou Jixing Metal Materials Co., Ltd. follows a rigorous multi-stage process optimized for dimensional accuracy, metallurgical quality, and surface integrity:
-
Raw Material Selection & Inspection (原材料检验)
Ingot or strip stock is sourced from certified stainless steel mills. Incoming materials undergo spectroscopic analysis (OES), chemical composition verification, and mechanical property testing to ensure compliance with specified alloy grades. -
Hot Rolling & Annealing (热轧与退火)
Continuous strip is hot-rolled to approximate dimensions, followed by controlled atmosphere annealing to eliminate residual stresses and achieve the desired microstructure (austenitic grain structure). -
Pickling & Descaling (酸洗与脱皮)
The strip undergoes acid pickling (nitric-hydrofluoric acid mixture) to remove oxide scale, followed by thorough rinsing and drying to prevent residual acid contamination. -
Cold Rolling (冷轧)
Multi-stand cold rolling reduces strip thickness to target specifications while improving surface finish and dimensional precision. Rolling schedules are optimized to control strain hardening and maintain ductility. -
Tube Forming & Seaming (制管与焊接)
The cold-rolled strip is fed through precision forming rolls to create the tubular geometry. A high-frequency induction welding (HFW) or laser welding process creates the longitudinal seam. The weld zone is subsequently trimmed and ground flush. -
Precision Sizing & Straightening (定径与矫直)
Multi-roller sizing stations ensure uniform outer diameter and wall thickness across the tube length. Inline straightening units eliminate any residual curvature. -
Intermediate Annealing (中间退火)
Tubes are annealed in a protective atmosphere (nitrogen or hydrogen-nitrogen mixture) at temperatures between 1050°C and 1150°C to relieve forming stresses, restore ductility, and refine the grain structure. -
Coiling & Winding (盘卷)
The finished tube is wound onto precision-mandrel coils using automated coiling equipment. Tension control systems ensure uniform coil formation without deformation or kinking. Each coil is labeled with heat number, grade, dimensions, and production date. -
Final Quality Inspection (终检)
Comprehensive testing includes dimensional verification (CMM, laser micrometry), ultrasonic testing (UT) for internal defects, eddy current testing (ECT) for surface and near-surface flaws, and hydrostatic pressure testing for leak integrity.
4.1 Process Flow Diagram (Schematic)
Raw Strip → Hot Rolling → Annealing → Pickling → Cold Rolling → Forming → Welding → Sizing → Intermediate Annealing → Coiling → Inspection → Packaging
5. Applications
Stainless steel coil tubes from Wenzhou Jixing Metal Materials Co., Ltd. serve a broad spectrum of industrial applications:
- Heat Exchangers & Radiators (换热器与散热器) — Coil tubes provide efficient heat transfer surfaces in compact configurations, widely used in HVAC systems, automotive radiators, and industrial heat exchangers.
- Food & Beverage Processing (食品加工) — The hygienic surface finish and corrosion resistance of grades 304/316L make coil tubes ideal for dairy equipment, brewing systems, and food-grade piping.
- Pharmaceutical Equipment (制药设备) — Bioreactor internals, CIP (Clean-in-Place) systems, and sterile transfer lines require the purity and weldability of stainless steel coil tubes.
- Chemical Processing (化工设备) — Reactor internals, condenser tubes, and corrosive fluid transfer lines benefit from the chemical inertness of austenitic stainless steels.
- Automotive Industry (汽车工业) — Catalytic converter substrates, exhaust system components, and fuel delivery lines utilize precision-formed stainless steel coil tubes.
- Oil & Gas (石油天然气) — Subsea production lines, wellhead assemblies, and offshore platform piping systems employ corrosion-resistant coil tubes.
- Medical Devices (医疗器械) — Surgical instrument handles, endoscope channels, and implantable device housings require the biocompatibility of medical-grade stainless steel.
- Architectural & Decorative (建筑装饰) — Handrails, elevator components, and architectural cladding utilize the aesthetic appeal and durability of polished stainless steel coil tubes.
6. Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management framework ensuring product conformity to international standards:
- ISO 9001:2015 — Quality Management System certification demonstrating consistent capability to meet customer and regulatory requirements
- ISO 14001:2015 — Environmental Management System ensuring sustainable manufacturing practices
- ISO 45001:2018 — Occupational Health and Safety Management System
- EN 10204 — Material Test Certificate (Type 3.1) issued for each production lot, providing full traceability
- ASTM/ASME Standards Compliance — Products manufactured and tested per ASTM A213, ASTM A269, and ASME B31.3 specifications
- CE Marking — Conformity with European directives for pressure equipment and machinery
- PED (Pressure Equipment Directive) 2014/68/EU — Compliance for pressure-rated applications
- NACE/AMPP MR0175 — Available for sour service applications requiring sulfide stress cracking resistance
6.1 Testing & Inspection Protocol
| Test Method | Standard | Frequency |
|---|---|---|
| Chemical Analysis (化学分析) | ASTM E415 (OES) | Per heat/lot |
| Tensile Testing (拉伸试验) | ASTM A370 | Per coil |
| Hardness Testing (硬度测试) | ASTM E92 (Rockwell B) | Per coil |
| Hydrostatic Testing (水压试验) | ASTM A530 | Per coil |
| Ultrasonic Testing (超声检测) | ASTM E1277 | Per coil |
| Eddy Current Testing (涡流检测) | ASTM E3 |