Sihe Steel
Sihe Steel
Explore our industrial grade seamless capillary, duplex, and heat exchanger tubing products.
A technical guide to selecting, specifying, and sourcing duplex stainless steel coiled lines.
For critical industries operating in aggressive environments—such as marine offshore drilling, heavy petrochemical refineries, and chemical processing facilities—material reliability is paramount. The selection of tubing standards and grades directly influences the lifespan, safety, and mechanical integrity of processing pipelines. ASTM A269 Duplex 2205 (UNS S31803 / S32205) coiled tubing represents a significant evolutionary step over traditional austenitic alloys (e.g., 304L and 316L), offering a dual-phase microstructure that balances high tensile strength and superior pitting resistance.
Duplex 2205 is characterized by a roughly equal ratio of austenite and ferrite phases (typically a 50/50 balance). This structural composition is achieved through precise chemical formulation, containing approximately 22% Chromium, 5% Nickel, 3% Molybdenum, and 0.18% Nitrogen. The presence of ferrite imparts high yield strength—nearly double that of conventional austenitic grades—and excellent resistance to Chloride Stress Corrosion Cracking (CSCC). Simultaneously, the austenitic phase ensures robust ductility and impact toughness even at sub-zero temperatures.
| Alloy Grade | Cr (%) | Ni (%) | Mo (%) | N (%) | PREN (Pitting Resistance Equivalent) |
|---|---|---|---|---|---|
| 316L (Austenitic) | 16.0 - 18.0 | 10.0 - 14.0 | 2.0 - 3.0 | < 0.10 | ~ 23 - 25 |
| Duplex 2205 (UNS S32205) | 22.0 - 23.0 | 4.5 - 6.5 | 3.0 - 3.5 | 0.14 - 0.20 | ≥ 35 (Typically 36) |
| Super Duplex 2507 (UNS S32750) | 24.0 - 26.0 | 6.0 - 8.0 | 3.0 - 5.0 | 0.24 - 0.32 | ≥ 40 (Typically 42) |
The ASTM A269 specification covers nominal-wall-thickness, seamless, and welded austenitic and duplex steel tubing for general service. For coiled tubing applications, seamless manufacturing is critical. Our proprietary precision cold-drawing and bright annealing technologies allow us to construct ultra-long continuous coiled tubes up to 10,000 meters (32,800 feet) without intermediate orbital weld joints. This seamless nature drastically reduces potential leak paths, mitigates turbulence in high-velocity fluid transfers, and ensures uniform mechanical behavior across the entire length of the umbilical or control line.
Liaocheng Sihe Stainless Steel Material Co., Ltd. - Scale, Technology & Global Logistics
As an industry-leading manufacturer, Liaocheng Sihe Stainless Steel Material Co., Ltd. operates six highly automated production lines. We utilize online bright annealing technology under controlled hydrogen atmospheres. This ensures the carbon elements in the steel remain dissolved, preventing carbide precipitation and producing a clean, scale-free, and shiny metallic surface that does not require pickling.
Our state-of-the-art testing equipment allows us to conduct a comprehensive series of quality control checks including 100% hardness tests, flaring, flattening, tensile, pneumatic/air tightness tests, and hydrostatic validations. This ensures every batch exported matches global expectations.
Liaocheng Sihe Stainless Steel Coiled Tubing Facility
Aligning with international engineering, procurement, and construction (EPC) requirements.
We manufacture in strict compliance with GB, ASTM, ASME, JIS, and EN standards. Our production processes are supported by comprehensive certifications including PED (Pressure Equipment Directive), ISO 9001 quality management, and Lloyd’s/DNV classifications for marine and offshore installations.
Modern offshore energy extraction operates in increasingly harsh deepwater basins. Our continuous duplex coiled tubes are designed for subsea umbilical assemblies, injecting chemicals and transferring hydraulic control fluids to wellheads under extreme safety margins.
For international transit, we wrap our coiled tubing on heavy-duty wooden or steel reels, packaged with moisture-resistant protective wraps. We ensure specialized hazard packaging and temperature-controlled containers for custom requests, minimizing shipping risks.
Precision Wound Steel Reels Ready for Global Export
Custom-fabricated solutions matching your dimensional and design parameters.
Supports precision bending, helical winding, and spiral configurations tailored for compact condenser coils and double-pipe heat exchangers. Available in 304, 316L, and Duplex 2205.
Equipped with state-of-the-art laser, mechanical, or flame cutting tools to produce precise pre-cut lengths. Multi-roller straightening machines ensure absolute tolerance control.
Specialized in producing flanged ends, flared terminations, and custom swaging to simplify field connections in automotive exhausts, instrument manifolds, and chemical pipelines.
Authorized documentations ensuring compliance with international manufacturing laws.
Engineered to deliver structural performance and chemical stability across challenging industrial sectors.
A breakdown of our manufacturing portfolio, highlighting key specifications and sizes.
2205 stainless steel is a duplex stainless steel containing austenitic and ferritic structures, engineered for ultimate safety.
1/2" stainless steel coiled tubing refers to custom length loops of corrosion-resistant instrumentation lines.
High-temperature heat exchanger coil solutions designed and produced inside our local facilities.
Key information regarding pricing, MOQs, engineering tolerances, and delivery of our coiled tubes.
Explore high-temp steels, custom capillary tubes, and industrial sheets.
