Sihe Steel
Sihe Steel
Browse our core inventory of high-performance duplex and alloy capillary solutions certified to global standards.
High-strength duplex 2205 capillary tubes offering excellent corrosion resistance in chloride environments.
Request Specifications
Super duplex alloy UNS S32750 delivering extreme protection against pitting and stress corrosion cracking.
Request Specifications
Bulk supply channels for premium duplex grade capillary systems optimized for high pressure operations.
Request Specifications
High-precision capillary lines manufactured in China adhering strictly to international ASTM/ASME standards.
Request Specifications
Continuous long-length coiled tubes for oil and gas umbilical systems and downhole instrumentation.
Request Specifications
Seamless execution ensures zero weld seams, minimizing risk during structural bending and high-pressure duties.
Request Specifications
Competitive pricing structure for global bulk procurement of custom tolerance capillary components.
Request Specifications
Standard sizing configurations engineered for precision instrumentation, control systems, and cooling panels.
Request SpecificationsDuplex 2205 (UNS S32205 / UNS S31803) represents a microstructural milestone in metallurgy. It is designed to combine the optimal characteristics of both austenitic and ferritic steels. The microstructure contains approximately 50% ferrite and 50% austenite, delivering a material profile that overcomes the low strength and cracking issues of traditional austenitic grades like AISI 316L, while avoiding the low toughness associated with pure ferritic alloys.
When drawn down into capillary dimensions (typically with outer diameters ranging from 0.125" to 0.50"), the material's structural integrity becomes even more critical. The high nitrogen, chromium, and molybdenum content in Duplex 2205 provides a Pitting Resistance Equivalent Number (PREN) of ≥ 35, calculated as follows:
PREN Formula: PREN = %Cr + 3.3(%Mo + 0.5%W) + 16%N
This higher PREN ensures that 2205 capillary tubing offers superior resistance to chloride-induced pitting and crevice corrosion compared to 316L (PREN ~23), making it a top choice for marine, subsea, and aggressive chemical processing plants.
At Liaocheng Sihe Stainless Steel Material LTD, we operate six advanced production lines dedicated to high-precision capillary and coiled tubing. By utilizing cold-drawing techniques alongside continuous bright annealing furnaces, we maintain strict dimensional controls (OD tolerance up to ±0.05mm) across continuous lengths up to 32,800 feet (10,000 meters).
Our online bright annealing technology, operating in a protective hydrogen atmosphere, prevents oxide scale formation on both internal and external walls. This yields a clean finish that is critical for applications involving high-purity gases and hydraulic fluids, such as semiconductors and analytical chromatography. This processing eliminates the need for aggressive acid pickling, preserving the metallurgical balance of the duplex structure.
We manufacture capillary and coiled tubing strictly in accordance with major international industrial standards.
| Parameter | Duplex 2205 Sizing & Specs | Super Duplex 2507 Sizing & Specs | Incoloy 825 / Inconel 625 Sizing |
|---|---|---|---|
| Outer Diameter (OD) | 0.125 in (3.175 mm) to 1.00 in (25.4 mm) | 0.125 in (3.175 mm) to 0.75 in (19.05 mm) | 0.062 in (1.57 mm) to 0.50 in (12.7 mm) |
| Wall Thickness (WT) | 0.010 in (0.25 mm) to 0.165 in (4.19 mm) | 0.015 in (0.38 mm) to 0.120 in (3.05 mm) | 0.008 in (0.20 mm) to 0.095 in (2.41 mm) |
| Max Length (Continuous) | Up to 32,800 feet (10,000 meters) | Up to 19,680 feet (6,000 meters) | Up to 16,400 feet (5,000 meters) |
| Execution Standards | ASTM A789, ASTM A790, EN 10216-5 | ASTM A789, ASTM A790, JIS G3459 | ASTM B163, ASTM B423, ASTM B704 |
| Testing Protocols | Eddy Current, Hydrostatic, Flaring, Hardness | Pneumatic, Bending, Intergranular Corrosion | Vacuum Leak Test, Tensile, Micrographic |
We provide comprehensive engineering adjustments, from metallurgy selection to mechanical finishing.
We support tailored wall thicknesses and custom outer diameters (from 3.175mm to 25.4mm) for seamless integration with specialized industrial machinery and tight installation tolerances.
We handle complex spatial shapes, tight-radius spiral coiling, and serpentine configurations designed for high-efficiency heat exchangers and analytical cooling coils.
Specialized polishing (chemical mechanical polishing or mechanical draw polishing) guarantees a low-roughness (Ra ≤ 0.4 μm) inner diameter surface, preventing flow friction and material scaling.
Equipped with high-precision orbital mechanical saws and CNC laser cutting tools, we deliver clean, burr-free perpendicular cuts that facilitate automated orbital welding.
Where extreme environmental challenges demand reliable corrosion-resistant materials.
Duplex 2205 offers twice the yield strength of 316L, allowing for thinner tube walls and higher heat transfer efficiency without compromising pressure containment.
Resists environmental corrosion and vibration fatigue, making it suitable for industrial chiller units and heat pumps.
Performs reliably when handling organic acids, chlorides, and sulfuric process lines under elevated operational temperatures.
The smooth internal surface structure prevents microbial accumulation, simplifies sanitization, and resists pitting from salty wash-downs.
Minimizes product contamination in ultra-high purity process streams, supporting standard clean-in-place (CIP) and steam-in-place (SIP) cycles.
Serves in steam condensers, feedwater heaters, and flue gas desulfurization systems where high chloride contents are present.
Widely deployed in deepwater subsea control lines, monitoring wells, chemical injection lines, and subsea hydraulic umbilical tubes.
Ensures reliable hydraulic pressure transfer in control systems, landing gear hydraulics, fuel lines, and high-vibration engine sensors.
We manufacture across a wide range of corrosion-resistant alloys to meet diverse industrial specifications.
Seamless long-length tubes in Duplex 2205, minimizing orbital welds in complex installations.
Strict dimensional tolerances and smooth internal bore for chromatography and instrumentation.
Austenitic grade with excellent oxidation resistance at temperatures up to 1100°C.
High molybdenum alloys designed to withstand intense pitting and crevice corrosion environments.
Optimized thermal conductivity and reliable fatigue strength for high-cycle thermal environments.
Nickel-based alloys offering high-temperature strength and corrosion resistance in reducing acids.
Specialty materials developed for high-stress aerospace components and deep-well exploration.
Ensures leak-tight connections in high-vibration systems and control panels.
Chemically inert internal walls designed for precise, consistent sample flow.
Long continuous coils designed to handle high external pressures in subsea umbilicals.
Supplied on heavy-duty steel reels, ready for integration into umbilical wrapping systems.
Prepared ends ready for critical connections in automotive exhaust and chemical pipelines.
Supports the assembly of heat exchanger shells, end caps, and mounting flanges.
We trace each batch of steel back to the ladle, ensuring conformance to ISO, PED, and material specification requirements.
Every shipment of our 2205 duplex capillary tubes includes a complete Mill Test Report (MTR) detailing the exact chemical composition, physical properties, heat numbers, and test results. Our testing protocol covers hydrostatic pressure testing, eddy current non-destructive examination (per ASTM E426), pneumatic air tightness testing, microstructural grain size analysis, and mechanical testing (yield, tensile, elongation, and hardness) to confirm compliance with ASTM A789 and EN 10216-5.
The global demand for high-strength, corrosion-resistant capillary tubing is growing, driven by the expansion of deep-sea exploration, offshore hydrogen production, and the push for higher processing efficiencies. As oil and gas extraction moves into deeper waters and harsher environments, umbilical control lines must withstand increasing hydrostatic pressures and corrosive seawater over decades-long lifespans.
Additionally, the growth of green hydrogen technology is creating new opportunities for Duplex 2205 and Super Duplex 2507 capillary tubes in high-pressure distribution lines and fuel-cell cooling systems. The material's resistance to hydrogen embrittlement makes it a reliable alternative to traditional alloys in high-pressure systems.
Common questions regarding our global supply capabilities, testing standards, and logistics.
Our pricing fluctuates based on global raw material costs (nickel, molybdenum, and chromium indices), requested tolerances, overall order volume, and packaging configurations (standard coils versus heavy-duty steel spools). Contact our sales team with your exact specifications for a detailed quote.
For standard sizes in Duplex 2205 and 316L, our minimum order quantity starts at 500 meters. Custom alloy grades (such as Inconel or Hastelloy) and specialized dimensional requirements are subject to custom production runs with MOQs determined on a case-by-case basis.
Yes. We supply Mill Test Certifications (MTRs) to EN 10204 3.1, raw material origin certificates, hydrostatic test reports, eddy current test charts, third-party inspection releases (DNV, Lloyd's, ABS), and standard export documents.
For standard sizes in stock, lead times are approximately 7 to 10 days. For custom production runs and large-scale bulk orders, lead times range from 20 to 30 days after drawing confirmation and deposit receipt, depending on alloy availability and current factory scheduling.
We typically accept a 30% deposit in advance by Telegraphic Transfer (T/T), with the remaining 70% balance paid against the copy of the Bill of Lading (B/L). We also accept Letter of Credit (L/C) at sight for large contract volumes.
We warranty our materials against manufacturing defects and dimensional non-compliance. Our quality assurance protocol tracks each production heat number from raw material to finished product to support long-term operational safety.
Yes. All long coiled tubes are wrapped on robust wooden or steel spools, protected by heavy plastic shrink-wrap, and boxed in reinforced seaworthy wooden crates to prevent damage during multi-modal international transit.
We support EXW, FOB, CFR, CIF, and DDP shipping terms. Large bulk shipments are typically transported via FCL sea freight from Qingdao or Shanghai ports. Urgent prototypes and sample draws can be dispatched via air freight or express carriers.
Explore our secondary line of specialized materials, heat exchanger piping, and high-performance alloys.
Polymer encapsulated duplex tubes designed to protect control lines from mechanical abrasion in downhole environments.
Request Specifications
High-nickel alloy tubing featuring excellent resistance to acid and chloride environments.
Request Specifications
High-purity capillary draws engineered for offshore instrumentation, subsea manifolds, and chemical injection.
Request Specifications
Commonly specified dimensions for analytical instrumentation and pilot plant hydraulic loops.
Request Specifications
Martensitic stainless steel sheets offering high mechanical strength and moderate corrosion resistance.
Request Specifications
Designed to resist localized corrosion and stress corrosion cracking in high-temperature chemical plants.
Request Specifications
Ferritic steel pipe solutions designed for decorative, structural, and exhaust gas applications.
Request Specifications
Standard instrumentation sizes providing reliable gas feed lines under high-temperature conditions.
Request Specifications