Stainless Steel Coil Tube (Coiltube) — Technical Product Specification

1. Product Overview

The Stainless Steel Coil Tube (Coiltube) is a continuous-length tubular product manufactured in coiled form, designed for high-volume processing and fabrication in industrial applications. Unlike discrete-length seamless or welded pipes, coil tubes are produced as long, flexible coils that can be cut to required lengths downstream, offering significant advantages in material utilization, logistics efficiency, and processing flexibility.

Wenzhou Jixing Metal Materials Co., Ltd supplies stainless steel coil tubes that meet international standards for dimensional accuracy, mechanical performance, and corrosion resistance. The product is particularly valued in applications where long, uninterrupted tube lengths are required, such as heat exchanger manufacturing, refrigeration systems, automotive radiators, and fluid conveyance networks.

Building upon industry benchmarks — including production scales demonstrated by leading manufacturers such as Hailiang Group, whose copper coil tube output exceeded 1,100 metric tons in a single month — the stainless steel coil tube market demands precision manufacturing capabilities, consistent metallurgical quality, and scalable production throughput.

2. Material & Properties

2.1 Material Grades

2.2 Chemical Composition (Typical — AISI 316L)

Element Specification (%)
C (Carbon) ≤ 0.030
Si (Silicon) ≤ 1.00
Mn (Manganese) ≤ 2.00
P (Phosphorus) ≤ 0.045
S (Sulfur) ≤ 0.030
Cr (Chromium) 16.50 – 18.50
Ni (Nickel) 10.00 – 14.00
Mo (Molybdenum) 2.00 – 3.00
N (Nitrogen) ≤ 0.10
Fe (Iron) Balance

2.3 Mechanical Properties (Annealed Condition)

Property Unit Minimum/Range
Tensile Strength (Rm) MPa ≥ 485
0.2% Proof Stress (Rp0.2) MPa ≥ 205
Elongation (A50) % ≥ 40
Hardness (HV30) — ≤ 210
Density g/cm³ 8.00
Thermal Conductivity (20°C) W/(m·K) 16.3
Thermal Expansion Coefficient (20–100°C) ×10⁻⁶/K 16.0

2.4 Surface Conditions

3. Specifications

Parameter Specification Range
Outer Diameter (OD) 3.0 mm – 60.3 mm (1/8" – 2")
Wall Thickness (WT) 0.20 mm – 3.00 mm
OD Tolerance ±0.05 mm – ±0.15 mm (per ASTM A269 / ASME B462)
WT Tolerance ±10% or ±0.025 mm (whichever is greater)
Roundness (Ovality) ≤ 0.10 mm
Coil Inner Diameter 100 mm – 250 mm (4" – 10")
Coil Outer Diameter 300 mm – 600 mm (12" – 24")
Coil Weight Up to 1,500 kg per coil
Tube Length (per coil) Continuous; typically 500 m – 5,000 m
End Condition Plain, chamfered, or beveled
Applicable Standards ASTM A269, ASTM A270, ASME B462, EN 10217, JIS G3459, GB/T 12771
Delivery Condition Annealed, Pickled & Passivated (P&P)

4. Manufacturing Process

4.1 Process Flow

  1. Strip Preparation: Cold-rolled stainless steel strip is received in coil form, inspected for surface quality, and slit to precise widths corresponding to the target tube outer diameter.
  2. Forming (Cold Roll Forming): The flat strip passes through a series of progressive roller dies that gradually transform the flat profile into a circular cross-section with a longitudinal seam.
  3. Welding (TIG / Laser): The formed tube seam is welded using Tungsten Inert Gas (TIG) welding or high-power fiber laser welding. Inert shielding gas (argon) ensures a clean, oxide-free weld root. Laser welding is preferred for thin-wall tubes (WT < 1.0 mm) due to its narrow heat-affected zone (HAZ).
  4. Inline Annealing (if applicable): For certain grades or applications requiring full solution treatment, the tube passes through an inline annealing furnace (atmospheric or vacuum) to relieve residual stresses and restore full austenitic microstructure.
  5. Pickling & Passivation: The tube is subjected to acid pickling (typically a mixture of nitric and hydrofluoric acid) to remove weld discoloration and surface oxides, followed by passivation treatment to establish a chromium-rich passive film for corrosion resistance.
  6. Coiling: The finished tube is wound onto a coil core with controlled tension to prevent deformation, kinking, or inter-coil marking.
  7. Quality Inspection & Packaging: Each coil undergoes dimensional verification, visual inspection, and (where required) destructive testing before being packaged with protective wrapping, edge protection, and shipping documentation.

4.2 Critical Process Parameters

5. Applications

5.1 Primary Application Sectors

5.2 Advantages of Coil Tube Format

6. Quality Certifications & Compliance

6.1 Manufacturing Certifications

6.2 Testing & Inspection Regime

7. Unique Selling Points

Integrated Precision: The coil tube format delivers the dimensional consistency of seamless tubing with the economic advantages of welded manufacturing — achieving cost reductions of 15–30% over equivalent seamless solutions while maintaining comparable mechanical and corrosion performance.

Scalable Throughput: Modern coil tube production lines achieve continuous output rates exceeding 1,000 metric tons per month, ensuring reliable supply for large-scale projects with tight delivery schedules.

Grade Flexibility: From standard austenitic grades (304/316L) to high-performance super-austenitic and duplex alloys, the manufacturing platform accommodates the full spectrum of stainless steel chemistries without tooling redesign.

Traceability: Every coil is associated with a unique heat number, enabling full metallurgical traceability from raw material mill certificates through final product delivery — critical for regulated industries (pharmaceutical, aerospace, nuclear).

Downstream Integration: Coil tubes are pre-conditioned for seamless integration into automated fabrication lines, including CNC bending, orbital welding, and laser cutting systems, reducing secondary processing time and labor costs.

8. Packaging & Delivery

9. Ordering Information

To place an order or request a quotation, please provide the following details: