Stainless Steel Coiltube (盘管) — Product Technical Specification
1. Product Overview
The Stainless Steel Coiltube (盘管) is a precision-engineered, continuously wound tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. (Product No. 1178). Unlike conventional straight pipes or seamless tubes, the coiltube is produced in a continuous helical or spiral coil configuration, offering exceptional flexibility in installation, superior thermal transfer performance, and outstanding resistance to thermal cycling stress. This product is particularly designed for applications involving heat exchange, refrigeration systems, industrial fluid transport, and cryogenic environments where rapid temperature fluctuations are common.
The coiltube's continuous geometry provides inherent mechanical advantages, including the ability to absorb thermal expansion and contraction without the need for additional expansion joints. The spiral winding pattern maximizes surface area per unit volume, making it ideal for compact heat exchanger designs. Wenzhou Jixing Metal Materials Co., Ltd. leverages advanced cold-forming and hot-rolling technologies to produce coiltubes with uniform wall thickness, precise dimensional tolerances, and consistent material properties throughout the entire coil length.
2. Material & Properties
2.1 Base Material Composition
The coiltube is fabricated from high-grade austenitic stainless steel, conforming to international material standards. The primary grades utilized include:
- ASTM A312 Type 304 / 304L (UNS S30400 / S30403) — General-purpose corrosion-resistant alloy with excellent formability
- ASTM A312 Type 316 / 316L (UNS S31600 / S31603) — Enhanced pitting and crevice corrosion resistance due to molybdenum addition
- ASTM A312 Type 321 (UNS S32100) — Stabilized grade with titanium addition for resistance to intergranular corrosion at elevated temperatures
- ASTM A312 Type 310S (UNS S31008) — High-temperature grade suitable for sustained service above 1000°C
2.2 Key Mechanical Properties
| Property | Type 304 (Solution Annealed) | Type 316 (Solution Annealed) | Standard Reference |
|---|---|---|---|
| Tensile Strength (抗拉强度) | ≥ 515 MPa (75 ksi) | ≥ 515 MPa (75 ksi) | ASTM A213/A312 |
| Yield Strength (屈服强度) | ≥ 205 MPa (30 ksi) | ≥ 205 MPa (30 ksi) | ASTM A213/A312 |
| Elongation (伸长率) | ≥ 40% (min. 50% for 304L) | ≥ 35% (min. 40% for 316L) | ASTM A213/A312 |
| Hardness (硬度) | ≤ 217 HB / ≤ 95 HRB | ≤ 217 HB / ≤ 95 HRB | ASTM A213/A312 |
| Density (密度) | 8.0 g/cm³ | 8.0 g/cm³ | — |
| Thermal Conductivity (热导率) at 100°C | 16.3 W/(m·K) | 16.3 W/(m·K) | — |
| Specific Heat (比热容) at 100°C | 0.503 J/(g·K) | 0.503 J/(g·K) | — |
| Linear Thermal Expansion (线性热膨胀系数) 20–100°C | 17.3 × 10⁻⁶ /K | 17.3 × 10⁻⁶ /K | — |
2.3 Chemical Composition (Typical, wt%)
| Element | Type 304 | Type 316 | Type 321 |
|---|---|---|---|
| Carbon (C) | ≤ 0.08 | ≤ 0.08 | ≤ 0.08 |
| Chromium (Cr) | 18.0 – 20.0 | 16.0 – 18.0 | 17.0 – 19.0 |
| Nickel (Ni) | 8.0 – 10.5 | 10.0 – 14.0 | 9.0 – 12.0 |
| Molybdenum (Mo) | — | 2.0 – 3.0 | — |
| Titanium (Ti) | — | — | 5 × (C) – 0.70 |
| Manganese (Mn) | ≤ 2.0 | ≤ 2.0 | ≤ 2.0 |
| Silicon (Si) | ≤ 1.0 | ≤ 1.0 | ≤ 1.0 |
| Phosphorus (P) | ≤ 0.045 | ≤ 0.045 | ≤ 0.045 |
| Sulfur (S) | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 |
2.4 Surface Finish Options
- Pickled and Passivated (酸洗钝化) — Standard finish with Ra ≤ 0.8 μm; provides a clean, corrosion-resistant surface
- 2B Cold-Rolled (2B冷轧) — Smooth, semi-reflective finish with Ra ≤ 0.4 μm
- Electropolished (电解抛光) — Ultra-smooth finish with Ra ≤ 0.1 μm; suitable for sanitary and pharmaceutical applications
- Brushed / Satin (拉丝/缎面) — Decorative finish with controlled grain direction
- Custom Surface Treatment — Available upon request for specialized applications
3. Specifications
3.1 Dimensional Specifications
| Parameter | Specification | Tolerance | Standard Reference |
|---|---|---|---|
| Outer Diameter (外径, OD) | 6.0 mm – 168.0 mm (¼" – 6⅝") | ±0.1 mm – ±0.3 mm (OD-dependent) | ASTM A312 / EN 10216-5 |
| Wall Thickness (壁厚, WT) | 0.5 mm – 12.0 mm | ±10% of nominal | ASTM A312 / EN 10216-5 |
| Coil Length (盘管长度) | Custom, typically 10 m – 500 m per coil | As specified by customer | — |
| Coil Inner Diameter (盘管内径) | 300 mm – 2000 mm | ±25 mm | — |
| Minimum Bend Radius (最小弯曲半径) | ≥ 3 × OD (cold bending) | — | ASTM A312 |
| Coil Pitch (盘管螺距) | Adjustable, typically OD + 5 mm to OD + 50 mm | ±1.0 mm | — |
3.2 Commonly Available Sizes (Representative)
| Nominal Size (DN) | OD (mm) | WT (mm) — Schedule 10S | WT (mm) — Schedule 40S | WT (mm) — Schedule 80S |
|---|---|---|---|---|
| DN 6 (¼") | 6.35 | 0.80 | 1.49 | 2.11 |
| DN 8 (⅜") | 9.53 | 0.80 | 1.65 | 2.77 |
| DN 10 (½") | 14.13 | 0.80 | 1.65 | 2.77 |
| DN 15 (¾") | 19.05 | 0.90 | 1.65 | 2.87 |
| DN 20 (1") | 26.67 | 1.00 | 2.11 | 3.38 |
| DN 25 (1¼") | 33.40 | 1.00 | 2.11 | 3.38 |
| DN 32 (1½") | 42.16 | 1.65 | 2.77 | 4.11 |
| DN 40 (2") | 48.26 | 1.65 | 3.05 | 5.08 |
| DN 50 (2½") | 60.33 | 1.65 | 3.91 | 5.56 |
| DN 80 (3") | 88.90 | 2.11 | 5.49 | 7.62 |
3.3 Operating Conditions
| Parameter | Type 304 | Type 316 | Type 321 | Type 310S |
|---|---|---|---|---|
| Maximum Operating Temperature (最高使用温度) | 870°C (1600°F) | 870°C (1600°F) | 980°C (1800°F) | 1150°C (2100°F) |
| Minimum Operating Temperature (最低使用温度) | −196°C (−320°F, LN₂) | −196°C (−320°F, LN₂) | −196°C (−320°F, LN₂) | −196°C (−320°F, LN₂) |
| Maximum Operating Pressure (最高工作压力) | Up to 40 MPa (design-dependent) | Up to 40 MPa (design-dependent) | Up to 40 MPa (design-dependent) | Up to 40 MPa (design-dependent) |
| Corrosion Resistance (耐腐蚀性) | Atmospheric, mild acids | Marine, chlorides, strong acids | High-temp oxidation | Extreme high-temp oxidation |
4. Manufacturing Process
4.1 Production Workflow
- Raw Material Selection & Inspection (原材料选择与检验) — Virgin stainless steel coils or billets are sourced from certified mills (e.g., Outokumpu, Sandvik, Nippon Steel, Baosteel). Each batch undergoes spectrographic analysis to verify chemical composition compliance with the specified ASTM/EN grade.
- Hot Rolling & Annealing (热轧与退火) — Billet material is reheated to temperatures between 1100°C and 1250°C and hot-rolled into a tubular blank. The rolled tube is then solution-annealed (固溶退火) at 1040°C – 1150°C, followed by rapid water quenching to achieve a fully austenitic microstructure with optimal mechanical properties.
- Cold Drawing & Forming (冷拔与成型) — The hot-rolled blank undergoes multiple passes of cold drawing through precision tungsten carbide dies to achieve the required outer diameter and wall thickness tolerances. Intermediate annealing cycles (中间退火) are performed between drawing passes to relieve accumulated cold work and prevent cracking. The final cold-worked tube is cold-formed into the helical coil configuration using CNC-controlled coiling machines.
- Coil Winding (盘管卷绕) — The straight tube is fed through a precision bending head that imparts a controlled helical curvature. The winding parameters — including coil pitch (螺距), coil inner diameter (盘管内径), and bend radius (弯曲半径) — are programmatically controlled to ensure geometric uniformity throughout the entire coil length. Wenzhou Jixing Metal Materials Co., Ltd. employs proprietary tension-control systems to prevent ovality and distortion during the coiling process.
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