Welded Stainless Steel Coil Tube for Fluid Conveyance — GB/T 24593
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. presents its premium-grade welded stainless steel coil tube manufactured in strict accordance with the Chinese national standard GB/T 24593 — the authoritative specification for welded stainless steel tubes used in fluid transport applications. This product is engineered for demanding industrial environments where corrosion resistance, mechanical integrity, and reliable fluid conveyance are paramount. Delivered in coil form, the tubing offers maximum handling flexibility, reduced material waste, and streamlined downstream processing for end users across multiple industries.
The coil tube is produced using advanced automatic welding technology, ensuring consistent weld quality, dimensional accuracy, and superior mechanical performance throughout the entire coil length. Each coil undergoes rigorous testing — including upsetting and flattening trials — to verify weld integrity and structural soundness under compressive and bending loads.
Material & Properties
The welded stainless steel coil tube is available in a range of austenitic and austenitic-ferritic stainless steel grades, providing users with the flexibility to match material properties to specific service conditions:
- 304 (06Cr19Ni10) — Excellent general-purpose corrosion resistance; suitable for most chemical, food, and pharmaceutical applications.
- 304L (022Cr19Ni10) — Low-carbon variant offering enhanced resistance to intergranular corrosion after welding; ideal for welded assemblies and high-temperature service.
- 316 (06Cr17Ni12Mo2) — Molybdenum-enhanced grade providing superior resistance to chlorides, acids, and marine environments.
- 316L (022Cr17Ni12Mo2) — Low-carbon 316 variant for critical welding applications and high-corrosion environments.
- 321 (06Cr18Ni11Ti) — Titanium-stabilized grade offering excellent resistance to intergranular corrosion at elevated temperatures.
- 310S (06Cr25Ni20) — High-temperature grade for service up to 1150°C (2094°F) in oxidizing atmospheres.
Key material properties include:
- Tensile Strength: Typically 515–720 MPa (75,000–104,000 psi), depending on grade and condition.
- Yield Strength: Minimum 205 MPa (29,700 psi) for annealed condition.
- Elongation: ≥ 35% (annealed condition), ensuring excellent formability for bending, flanging, and upsetting operations.
- Corrosion Resistance: Superior resistance to atmospheric, chemical, and food-grade corrosive media.
- Temperature Range: Service from cryogenic temperatures (−196°C / −321°F) up to 870°C (1,598°F) for standard grades; up to 1,150°C (2,094°F) for 310S.
- Non-magnetic (annealed): Austenitic grades are essentially non-magnetic, making them suitable for applications where magnetic permeability is a concern.
Specifications
| Parameter | Specification |
|---|---|
| Standard | GB/T 24593 — Welded Stainless Steel Tubes for Fluid Conveyance |
| Product Type | Welded Stainless Steel Coil Tube |
| Outer Diameter (OD) | 3.00 – 50.80 mm (0.118" – 2.000") |
| Wall Thickness | 0.25 – 4.00 mm (0.010" – 0.157") |
| Coil Length | Customizable; typically 500 – 3,000 m (1,640 – 9,843 ft) per coil |
| Surface Finish | Pickled & Passivated (PP), Bright Annealed (BA), or custom finishes |
| Available Grades | 304, 304L, 316, 316L, 321, 310S, and others per customer requirement |
| Welding Process | Automatic orbital TIG (GTAW) welding with inert gas shielding |
| Weld Bead Quality | Smooth, uniform, fully fused weld seam; ground flush to within 0.05 mm (0.002") of outer surface |
| Dimensional Tolerance | OD: ±0.05 mm (±0.002"); Wall Thickness: ±10% of nominal |
| Upsetting Test | Complies with GB/T 24593 requirements — no cracking or separation at weld seam |
| Flattening Test | Complies with GB/T 24593 requirements — no cracking or separation at weld seam |
| Hydrostatic/Pneumatic Test | Available upon request; leak-free verification at specified pressure |
| Packaging | Export-standard coil packaging with moisture-proof wrapping, wooden pallets, and steel banding |
Manufacturing Process
The production of Wenzhou Jixing's welded stainless steel coil tube follows a meticulously controlled multi-stage process to ensure consistent quality and compliance with GB/T 24593:
- Raw Material Selection: Only certified stainless steel strip from approved mills is procured. Incoming material is verified for chemical composition, mechanical properties, and surface quality through spectroscopic analysis and mill test report (MTR) review.
- Strip Uncoiling & Straightening: The stainless steel strip is uncoiled and fed through precision straightening rollers to ensure consistent flatness and tension, critical for uniform weld formation.
- Forming: The flat strip is progressively formed into a tubular shape using a series of precision rollers. The forming process is carefully calibrated to prevent work hardening, surface defects, or dimensional deviation.
- Welding: The formed tube is welded using automatic orbital TIG (GTAW) welding with high-purity argon shielding gas on both the inside and outside of the weld seam. This process produces a clean, fully fused weld with minimal heat-affected zone (HAZ), ensuring superior mechanical and corrosion properties at the weld.
- Weld Bead Grinding: The external weld bead is ground smooth and flush to within 0.05 mm (0.002") of the outer surface, ensuring a uniform surface profile and eliminating stress concentration points.
- Heat Treatment (Annealing): Where specified, the welded coil tube is subjected to solution annealing at 1050–1150°C (1,922–2,092°F) followed by rapid cooling to restore full austenitic microstructure, relieve residual welding stresses, and maximize corrosion resistance.
- Pickling & Passivation: The tube is chemically pickled to remove oxide scale and passivated to form a protective chromium oxide layer, ensuring long-term corrosion resistance and a clean, hygienic surface finish.
- Dimensional Inspection: Outer diameter, wall thickness, and straightness are measured at regular intervals using calibrated instruments to verify compliance with GB/T 24593 dimensional tolerances.
- Mechanical & Weld Integrity Testing: Samples are subjected to upsetting tests and flattening tests as required by GB/T 24593 to verify weld seam integrity under compression and bending loads. Additional hydrostatic or pneumatic pressure testing is performed to confirm leak-free performance.
- Final Inspection & Packaging: Each coil is visually inspected for surface defects, marked with identification tags, and packaged in export-standard protective packaging for safe transportation.
Applications
Wenzhou Jixing's GB/T 24593 welded stainless steel coil tube is designed for fluid conveyance and is widely used across a diverse range of industries:
- Food & Beverage Industry: Milk processing lines, beverage transfer systems, dairy equipment, and sanitary fluid conveyance where hygienic surface finishes and corrosion resistance are critical.
- Pharmaceutical Industry: CIP (Clean-in-Place) systems, sterile fluid transfer, process piping, and instrument tubing in pharmaceutical manufacturing facilities.
- Chemical Processing: Transfer of aggressive chemicals, acids, alkalis, and solvents in chemical plants and refineries.
- Water Treatment & Desalination: Municipal water supply systems, wastewater treatment, desalination plants, and reverse osmosis (RO) systems.
- Oil & Gas Industry: Instrument tubing, process lines, and fluid transfer in upstream and downstream petroleum operations.
- Power Generation: Boiler feedwater systems, cooling circuits, and steam lines in thermal and nuclear power plants.
- Automotive & Transportation: Fuel lines, brake systems, exhaust systems, and hydraulic fluid conveyance in vehicles and rail systems.
- Medical Devices: Instrument tubing, endoscope channels, and fluid lines in medical equipment manufacturing.
- Construction & Architecture: Decorative railings, structural tubing, and building envelope components.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a robust quality management framework to ensure every product meets or exceeds international and national standards:
- GB/T 24593 — Chinese National Standard for Welded Stainless Steel Tubes for Fluid Conveyance (primary compliance standard).
- ISO 9001:2015 — Quality Management System certification ensuring consistent process control and continuous improvement.
- ISO 3834 — Quality requirements for welding of metallic materials, covering welding procedure qualification and welder certification.
- EN 10204 Type 3.1 — Inspection certificates issued by authorized inspection personnel, providing full traceability of material and test results.
- Material Traceability: Each coil is accompanied by a mill test report (MTR) with full chemical composition, mechanical properties, and test results traceable to the heat number of the raw material.
- Upsetting & Flattening Test Compliance: All weld seams are tested per GB/T 24593 requirements, with documented evidence of passing results included in the inspection certificate.
Unique Selling Points
Superior Weld Quality — Engineered for Integrity. Wenzhou Jixing's welded coil tube features a precision-ground, fully fused orbital TIG weld seam that passes upsetting and flattening tests without cracking or separation. This ensures reliable performance even when the tube is subjected to bending, forming, or compression during installation and service.
- Comprehensive Standard Compliance: Manufactured strictly to GB/T 24593 with additional alignment to international standards (ASTM, EN, JIS), providing global market accessibility.
- Wide Grade & Size Range: Multiple stainless steel grades and dimensions available from a single source, simplifying procurement and reducing supply chain complexity.
- Coil Form Advantage: Delivered in coil form for maximum cutting efficiency, reduced scrap, and seamless integration with automated tube processing equipment (cut-to-length, bending, end-finishing).
- Full Traceability: Complete material traceability from raw strip to finished coil, with certified test reports for every lot.
- Customization Capability: Flexible customization of coil length, surface finish, end treatment, and packaging to meet specific customer requirements.
- Cost-Effective Alternative: Welded coil tube provides a competitive-cost solution compared to seamless tubing while maintaining comparable mechanical and corrosion performance for most fluid conveyance applications.
Conclusion
Wenzhou Jixing Metal Materials Co., Ltd.'s welded stainless steel coil tube to GB/T 24593 represents a benchmark product in the Chinese stainless steel tubing market. Combining advanced manufacturing technology, rigorous quality control, and comprehensive standard compliance, this product delivers the reliability, corrosion resistance, and versatility required for critical fluid conveyance applications worldwide. Whether for sanitary food processing, aggressive chemical service, or demanding industrial systems, Wenzhou Jixing provides a trusted solution backed by proven quality and competitive value.