Seamless Stainless Steel Heat Exchanger Coil Tube — GB/T 13296 Standard
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. offers premium-grade seamless stainless steel coil tubes engineered specifically for heat exchanger applications in accordance with the Chinese National Standard GB/T 13296. These precision-manufactured tubes are designed to deliver exceptional thermal transfer efficiency, outstanding mechanical integrity, and long-term corrosion resistance under demanding industrial operating conditions. Available in a continuous coil configuration, these tubes facilitate efficient downstream processing, including cold drawing, sizing, and forming into U-bends or custom geometries required for shell-and-tube heat exchangers, condensers, evaporators, and reboilers.
The seamless construction eliminates weld seams that could serve as stress concentration points or corrosion initiation sites, ensuring superior fatigue life and leak-tight performance throughout the service life of the equipment.
Material & Properties
Our seamless heat exchanger coil tubes are manufactured from a range of austenitic and duplex stainless steel grades, including but not limited to:
- 304 / 304L (06Cr19Ni10) — Excellent general-purpose corrosion resistance with low carbon variant for improved weldability and intergranular corrosion resistance
- 316 / 316L (06Cr17Ni12Mo2) — Enhanced resistance to chlorides, acids, and marine environments due to molybdenum addition
- 321 (06Cr18Ni11Ti) — Titanium-stabilized grade offering superior resistance to intergranular corrosion at elevated temperatures
- 310S (06Cr25Ni20) — High-temperature grade suitable for severe oxidation and scaling environments
- 904L (06Cr23Ni28Mo2CuN) — Ultra-high alloy grade for extreme corrosive environments
- 2205 Duplex (S31803) — High-strength duplex stainless steel with superior resistance to chloride stress corrosion cracking
Key Performance Characteristics
- Intergranular Corrosion Resistance: Tubes undergo rigorous intergranular corrosion testing (ASTM A262 Practice E or equivalent) to verify resistance to sensitization, particularly critical for 304L and 321 grades in welding and high-temperature service
- U-Bend Test Compliance: All tubes pass the mandatory U-bend (cold bending) test per GB/T 13296 requirements, demonstrating ductility and cold-workability essential for forming into heat exchanger bundle configurations
- Elevated NDT Inspection Ratio: Higher-than-standard non-destructive testing coverage ensures freedom from internal defects, laminations, and surface discontinuities
Specifications
| Parameter | Specification / Range |
|---|---|
| Applicable Standard | GB/T 13296 — Seamless Steel Tubes for Heat Exchangers and Heat Transfer Equipment |
| Outer Diameter (OD) | Φ6.0 mm – Φ159.0 mm |
| Wall Thickness | 0.5 mm – 12.0 mm |
| Delivery Form | Continuous Coil (Coil Tube) |
| Manufacturing Method | Seamless (Hot-Rolled, Warm-Rolled, or Cold-Drawn) |
| Surface Finish | Pickled & Passivated, Bright Annealed, or Mill Finish |
| Surface Roughness (Ra) | ≤ 0.8 μm (polished finish available upon request) |
| Tolerance (OD) | ±0.15 mm or per agreed tolerance class |
| Tolerance (Wall Thickness) | ±10% of nominal or per agreed tolerance class |
| Coil Weight | Typically 200 – 1,000 kg per coil |
| U-Bend Test | Compliant with GB/T 13296 / ASTM A314 — 180° bend, 4D minimum bend diameter |
| Hydrostatic Test | 100% tested per GB/T 13296 requirements |
| NDT Inspection | Eddy Current Testing (ET) — 100% of tube length; UT/RT on specified lots |
| Intergranular Corrosion Test | ASTM A262 Practice E (or equivalent) — 100% pass |
| Chemical Analysis | 100% per heat — certified to grade specification |
| Heat Treatment | Solution Annealing (1010–1150°C + rapid cooling) or Stabilization Treatment (for 321) |
| Packaging | Steel banding, protective caps, wooden pallets, or export-grade packaging |
Manufacturing Process
The production of seamless heat exchanger coil tubes at Wenzhou Jixing follows a tightly controlled multi-stage process:
- Raw Material Selection: High-purity stainless steel billets or slabs sourced from certified mills, with full chemical and mechanical traceability
- Piercing & Hot Rolling: Billets are heated to 1,200–1,300°C and pierced through a mandrel to produce seamless hollow sections, followed by hot rolling to initial dimensions
- Intermediate Annealing: Tubes are solution-annealed to relieve hot-working stresses and restore full austenitic microstructure
- Pickling & Passivation: Surface oxide scale is removed via acid pickling; a protective chromium oxide passive layer is established
- Cold Drawing / Cold Rolling: Tubes are cold-worked to final OD and wall thickness tolerances, improving dimensional accuracy, surface finish, and mechanical properties
- Final Annealing & Pickling: Ensures uniform microstructure, eliminates cold-work stresses, and restores corrosion resistance
- Coiling: Finished tubes are wound onto precision coils with controlled tension to prevent deformation or surface damage
- Comprehensive Testing: Every coil undergoes hydrostatic pressure testing, eddy current NDT, U-bend testing, and intergranular corrosion verification
Quality Certifications & Testing Protocol
Quality assurance is paramount to our commitment to reliable heat exchanger performance. Every production lot is subject to the following verification:
- GB/T 13296 Compliance: Full conformance to the Chinese National Standard for seamless steel tubes used in heat exchangers and heat transfer equipment
- Hydrostatic Test: 100% of tubes tested to proof pressure (typically 1.5× working pressure) with zero permeation allowed
- Eddy Current Testing (ET): 100% of tube length inspected for internal and external defects, including laminations, cracks, and wall thinning — exceeding the minimum NDT ratio required by standard
- U-Bend (Cold Bending) Test: Verified ductility and crack-free performance at 4D bend diameter under 180° bending per ASTM A314 / GB/T 13296
- Intergranular Corrosion Test: ASTM A262 Practice E (or GB/T 4334 equivalent) — confirms resistance to sensitization-induced grain boundary attack
- Dimensional Inspection: OD, wall thickness, and roundness verified per tolerance class on every coil
- Material Certification: Full chemical composition and mechanical property report per heat number (EN 10204 3.1 Certificate of Conformity)
- Mill Test Reports (MTR): Traceable documentation from raw material through final product
Applications
Our GB/T 13296 seamless stainless steel heat exchanger coil tubes are widely deployed across industries where thermal efficiency, corrosion resistance, and structural integrity are critical:
- Petrochemical & Oil Refining: Shell-and-tube heat exchangers, condensers, reboilers, and air coolers in refining and petrochemical processing
- Power Generation: Boiler tubes, economizers, superheaters, and feedwater heaters in thermal power plants
- Pharmaceutical & Food Processing: Sanitary heat exchangers for pasteurization, sterilization, and CIP-compatible thermal systems
- Chemical Processing: Heat exchangers handling aggressive acids, caustics, and chlorinated process streams
- Marine & Offshore: Condensers, evaporators, and thermal systems in marine propulsion and offshore platforms
- HVAC & Refrigeration: Air conditioning chillers, heat recovery systems, and industrial refrigeration condensers
- Pulp & Paper Industry: Recovery boilers, digesters, and condensate recovery heat exchangers
- Energy & Renewable: Geothermal heat exchangers, solar thermal systems, and hydrogen processing equipment
Unique Selling Points
- Higher NDT Inspection Ratio: Beyond the minimum standard requirements, we implement enhanced eddy current and ultrasonic testing coverage, significantly reducing the probability of defect escape and ensuring superior batch uniformity
- Verified U-Bend Performance: Every production lot demonstrates crack-free 180° U-bending at 4D minimum diameter, guaranteeing reliable forming performance for heat exchanger bundle manufacturing
- Proven Intergranular Corrosion Resistance: Rigorous ASTM A262 testing confirms microstructural stability, ensuring long-term service life in sensitization-prone environments
- Seamless Integrity: The absence of longitudinal welds eliminates the primary failure mode in heat exchanger tubes, providing superior fatigue resistance and leak-tight assurance
- Coil Delivery Advantage: Continuous coil format maximizes utilization, minimizes off-cuts, and streamlines downstream cold-drawing and forming operations for heat exchanger manufacturers
- Full Traceability: Complete heat-number traceability from raw material to finished coil with EN 10204 3.1 mill certificates
- Customization Capability: Flexible tolerance classes, surface finishes, and grade options tailored to specific OEM and end-user requirements
Conclusion
Wenzhou Jixing Metal Materials Co., Ltd. delivers GB/T 13296-compliant seamless stainless steel heat exchanger coil tubes that combine dimensional precision, metallurgical excellence, and comprehensive quality verification. Whether for demanding petrochemical service, sanitary pharmaceutical applications, or high-temperature power generation, our coil tubes provide the reliability and performance that critical thermal systems demand. Contact our technical sales team for grade selection guidance, sample testing, and customized specifications.