Stainless Steel Coil Tube with Pneumatic Pressure Testing – Wenzhou Jixing Metal Materials Co., Ltd.

Product Overview

Wenzhou Jixing Metal Materials Co., Ltd. supplies high-performance stainless steel coil tubes engineered for demanding industrial applications requiring superior pressure integrity, corrosion resistance, and dimensional precision. The coil tube product line is manufactured to international standards and undergoes rigorous non-destructive testing (NDT) protocols, including pneumatic pressure testing, to ensure zero-defect delivery to end users.

Coil tubes are supplied in continuous lengths wound onto spools, offering installation flexibility, reduced joint requirements, and enhanced flow characteristics compared to straight-length tubing. This makes them particularly suitable for heat exchangers, process piping systems, cryogenic applications, and high-pressure fluid transport where seamless integrity is paramount.

Material & Properties

Specifications

Parameter Specification
Outer Diameter (OD) 3.0 mm – 159.0 mm (1/8" – 6")
Wall Thickness 0.3 mm – 8.0 mm (0.012" – 0.315")
Coil Length Up to 100 m per coil (configurable)
Surface Finish Pickled & Passivated (2B), Mirror (No. 4 / #8), Matte, Custom
End Condition Plain, Beveled, Threaded, or Custom Perforation
Applicable Standards ASTM A213, ASTM A269, EN 10216-5, GB/T 12771, JIS G3459
Design Pressure Rating Up to 40 MPa (5,800 psi), grade-dependent
Testing Standard ASME BPV Code Section VIII, EN 13480, GB/T 24511

Manufacturing Process

Production Workflow

  1. Raw Material Procurement: Certified stainless steel bars and ingots from approved mills with full traceability documentation.
  2. Hot Rolling & Piercing: Seamless tube production via rotary piercing or Mannesmann method to achieve initial hollow form.
  3. Cold Drawing / Cold Rolling: Multi-pass reduction to achieve final OD, wall thickness, and dimensional tolerances (±0.05 mm).
  4. Heat Treatment: Solution annealing at 1,050–1,150 °C (1,922–2,092 °F) followed by controlled cooling to restore full austenitic microstructure.
  5. Pickling & Passivation: Chemical removal of oxide scale and formation of protective chromium oxide layer for corrosion resistance.
  6. Coiling: Continuous tube wound onto precision spools with controlled tension to prevent deformation.
  7. Non-Destructive Testing (NDT):
    • Eddy current inspection for wall integrity and surface defects
    • Visual examination per ASTM E1011
    • Dimensional verification using laser gauging
  8. Pressure Testing (Pneumatic – see below): Final pressure integrity verification.
  9. Final Inspection & Packaging: Protective end caps, desiccant wrapping, and export-grade crating.

Pneumatic Pressure Testing – Compressed Air / Nitrogen Hold Test

Critical Quality Gate: Pneumatic pressure testing is classified as a high-risk procedure and is conducted only when hydraulic (water) pressure testing is technically infeasible—such as for cryogenic service tubes, tubes with internal coatings, or assemblies where water ingress is unacceptable. All pneumatic tests require prior written approval from the quality assurance department and designated engineering authority.

The pneumatic pressure test protocol follows a rigorous safety and verification sequence:

  1. Pre-Test Preparation:
    • Full visual and dimensional inspection completed prior to pressurization
    • Test equipment calibrated and certified within valid interval
    • Exclusion zone established (minimum 5× the burst radius) to protect personnel
    • Written test authorization signed by QA manager and shift supervisor
  2. Test Medium: Compressed dry air or high-purity nitrogen (≥99.9% purity) to eliminate moisture and oxidation risks.
  3. Test Pressure: 1.1× the design pressure of the tube or assembly, applied gradually to avoid thermal shock or sudden stress concentration.
  4. Hold Time: Pressure maintained for a minimum of 30 seconds (or as specified by applicable code) to allow detection of any pressure drop indicative of leakage.
  5. Leak Detection Method:
    • Soap solution application: Concentrated surfactant solution applied to all joints, welds, and suspected leak paths; bubble formation indicates leakage.
    • Water immersion method: Tube submerged in water bath; rising bubble observation confirms seal integrity.
  6. Depressurization: Slow, controlled venting through calibrated needle valve to prevent pressure wave damage.
  7. Documentation: Test results recorded on individual batch traceability certificates including: test medium, pressure achieved, hold duration, ambient temperature, inspector ID, and pass/fail determination.

Safety Controls for Pneumatic Testing

Applications

Quality Certifications & Compliance

Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system ensuring full traceability and compliance with international standards:

Unique Selling Points

Technical Support & Ordering Information

Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive pre-sales engineering support including material selection guidance, pressure rating calculations, and test protocol planning. Custom coil configurations are available with lead times of 15–30 business days for standard orders and 30–45 days for specialized alloy or dimension requirements. All orders include a dedicated quality dossier with test certificates, dimensional reports, and compliance documentation.