Stainless Steel Coil Tube (Coiltube) – Exhaust Pulsation-Resistant Series | Wenzhou Jixing Metal Materials Co., Ltd

1. Product Overview

The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd is a precision-engineered continuous coil-form tubing product specifically designed for high-performance exhaust and fluid transport applications. This product is particularly optimized for use in compressor exhaust systems, where it must withstand significant pressure pulsations, thermal cycling, and continuous mechanical fatigue over extended service lifetimes.

Drawing upon advanced computational fluid dynamics (CFD) simulation and structural optimization methodologies — as documented in the technical study "Exhaust Pulsation Simulation and Structural Optimization of Compressor Exhaust Coil Tubes" — this coil tube series incorporates geometry refinements that significantly enhance fatigue resistance, reduce vibration-induced stress concentrations, and improve overall system reliability under dynamic operating conditions.

The coil tube is supplied in continuous coil form, enabling efficient downstream processing such as cutting, bending, welding, and heat exchanger assembly without the introduction of additional mechanical stresses at seam joints.

2. Material & Properties

The coil tube is fabricated from austenitic stainless steel grades conforming to international standards, ensuring superior corrosion resistance, high-temperature strength, and excellent formability.

2.1 Primary Alloy Grades

2.2 Key Mechanical and Physical Properties (AISI 304 Reference)

2.3 Corrosion Resistance

The austenitic microstructure, stabilized by chromium (Cr ≥ 18%) and nickel (Ni ≥ 8%) content, provides a robust passive oxide film (Cr₂O₃) that protects the substrate against atmospheric, aqueous, and many chemical environments. The 316 and 316L grades, with 2–3% molybdenum (Mo), offer enhanced resistance to chloride-induced pitting and stress corrosion cracking (SCC).

3. Technical Specifications

Parameter Specification Standard Reference
Outer Diameter (OD) 6.0 mm – 50.8 mm (1/4" – 2") ASTM A213 / GB/T 12771
Wall Thickness (WT) 0.5 mm – 3.0 mm ASTM A269 / EN 10217-7
Coil Inner Diameter (CID) 150 mm – 600 mm (configurable) Custom / Manufacturer Standard
Coil Length (per coil) 100 m – 3000 m (typical) —
Coil Weight (per coil) 50 kg – 1500 kg (depending on specification) —
Manufacturing Method Seamless (hot/cold drawn) or Welded (ERW/AW) ASTM A213 / ASTM A269
Surface Finish Pickled & Passivated (P&P), Polished, or Brushed ASTM A403 / GB/T 4237
Tolerance – OD ±0.10 mm (standard); ±0.05 mm (precision grade) ASTM A213 / EN 10217
Tolerance – WT ±10% of nominal (standard); ±5% (precision grade) ASTM A269
Roundness (Ovality) ≤ 1% of OD ASTM A213
Heat Treatment Solution Annealed at 1050–1150 °C, followed by water or air quench ASTM A213
Minimum Bend Radius ≥ 3× OD (cold bending without filler) ASME B31.3
Maximum Working Pressure Up to 15 MPa (depends on OD/WT combination) ASME B31.3 / EN 13480
Delivery Condition Coiled, protected with paper wrap, PE film, or wooden crate packing ISO 11607

4. Manufacturing Process

The production of the stainless steel coil tube at Wenzhou Jixing Metal Materials Co., Ltd follows a rigorous, multi-stage manufacturing workflow designed to ensure dimensional accuracy, metallurgical integrity, and surface quality:

4.1 Seamless Tube Manufacturing Route

  1. Hot Rolling / Extrusion: Stainless steel billets are heated to 1100–1200 °C and pierced or extruded through dies to produce hollow round tubes.
  2. Hot Resizing: Tubes are passed through a series of rolling stands to achieve approximate final dimensions.
  3. Solution Annealing: Tubes are reheated to 1050–1150 °C in a controlled-atmosphere furnace to dissolve carbides and restore full austenitic structure, followed by rapid cooling (water quench or controlled air cooling).
  4. Pickling & Passivation: Tubes are immersed in a hydrochloric acid or citric acid bath to remove oxide scale, followed by passivation treatment to re-establish the protective chromium oxide layer.
  5. Cold Drawing / Cold Rolling: Tubes are drawn through precision tungsten carbide or hardened steel dies to achieve exact dimensional tolerances, improved surface finish, and enhanced mechanical properties.
  6. Intermediate Annealing: Where multiple cold-drawing passes are required, intermediate solution annealing is performed to relieve work-hardening and maintain ductility.
  7. Coiling: Finished tubes are wound onto coil reels at controlled tension to prevent kinking, deformation, or surface damage.

4.2 Welded Tube Manufacturing Route (Alternative)

  1. Strip Preparation: Precision stainless steel strip is slit to the required width and inspected for surface defects.
  2. Forming & Welding: The strip is formed into a tube shape and welded using Electric Resistance Welding (ERW) or Automatic Welding (AW) processes.
  3. Weld Heat-Affected Zone (HAZ) Treatment: The weld zone is solution annealed to ensure metallurgical homogeneity.
  4. Finishing & Coiling: Surface finishing, dimensional verification, and coiling as per the seamless route.

4.3 Structural Optimization for Exhaust Pulsation Resistance

Based on computational fluid dynamics (CFD) and finite element analysis (FEA) simulations of exhaust gas pulsation dynamics within compressor discharge lines, the coil tube geometry and wall thickness distribution have been optimized to:

5. Applications

5.1 Primary Applications

5.2 Secondary Applications

6. Quality Certifications & Standards Compliance

Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management system and adheres to the following international standards and certifications:

6.1 Quality Management System

6.2 Product Standards

6.3 Industry-Specific Certifications

6.4 Testing & Inspection

Every batch of coil tube is subjected to comprehensive quality assurance procedures, including but not limited to:

7. Unique Selling Points

Pulsation-Resistant Structural Optimization: This coil tube series incorporates geometry and wall-thickness optimization derived from rigorous CFD and FEA simulation of compressor exhaust pulsation dynamics, resulting in demonstrably improved fatigue life and reduced vibration transmission compared to conventional coil tubes of equivalent specification.