Sihe Steel
Sihe Steel
Explore our primary selection of high-performance seamless coiled tubing, capillary configurations, and precision alloy tubes engineered for extreme corrosion resistance.
In modern industrial fluid networks, control systems, and downhole offshore installations, the integrity of subsea pipelines is critical. Seamless coiled tubing represents a significant advancement over standard jointed straight piping. By eliminating orbital weld joints across vast lengths (up to 10,000 meters or 32,800 feet), seamless coiled tubes reduce structural vulnerabilities, minimize potential leak points, and ensure uniform pressure boundary dynamics throughout the entire circuit.
Our manufacturing facility at Liaocheng Sihe Stainless Steel Material LTD designs and constructs these continuous alloy pathways specifically to combat extreme environments. Under deep sea conditions, corrosive sour gases, high thermal pressure cycles, and subsea physical stresses make high-alloy steels essential. Our products are engineered to withstand these environments, delivering reliable performance and long-term durability.
Our metallurgy portfolio covers everything from classic austenitic grades (such as 304, 304L, 316L, 321, 317L, 309S, 310S, and INCOLOY 800) to duplex, super duplex (Duplex 2205, Super Duplex 2507), and nickel-iron-chromium superalloys (Incoloy 825, Inconel 625). Each class of steel is processed through precise thermal cycles to ensure optimal corrosion resistance and strength.
Liaocheng Sihe manufactures high-precision seamless coiled tubes to precise tolerances under international specifications. Review our standard dimensional boundaries and alloy options below.
| Material Class | Common Alloy Designations | Outside Diameter (OD) Range | Wall Thickness (WT) Range | Compliance Standards | Primary Industrial Properties |
|---|---|---|---|---|---|
| Austenitic Alloys | 304/304L, 316L, 321, 317L, 309S, 310S | 0.125" to 1.000" (3.175 - 25.4 mm) | Up to 0.165" (3.00 mm) | ASTM A269, A213, EN 10216-5, JIS G3459 | High ductility, excellent general corrosion resistance, cryogenic stability. |
| Duplex Steels | Duplex 2205 (UNS S31803 / S32205) | 0.250" to 1.000" (6.35 - 25.4 mm) | Up to 0.120" (3.05 mm) | ASTM A789, ASME SA789, EN 10216-5 | High yield strength, excellent resistance to chloride stress corrosion cracking (SCC). |
| Super Duplex | Super Duplex 2507 (UNS S32750) | 0.250" to 0.750" (6.35 - 19.05 mm) | Up to 0.100" (2.54 mm) | ASTM A789, API 5LC | PREN > 40. High resistance to pitting and crevice corrosion in marine environments. |
| Nickel Superalloys | Incoloy 825 (UNS N08825), Inconel 625 (UNS N06625), INCOLOY 800 | 0.125" to 0.750" (3.175 - 19.05 mm) | Up to 0.095" (2.41 mm) | ASTM B163, B423, B444, ASME SB444 | Superior resistance to phosphoric, sulfuric acids, and sour gas (H2S + CO2) environments. |
How Liaocheng Sihe integrates raw material selection, advanced bright annealing, and global supply networks to ensure reliable product delivery.
Operating six dedicated cold drawing and bright annealing production lines, our facility is designed for large-scale production. We source high-purity alloy raw materials from major steel suppliers, securing a steady input flow even during global supply shifts.
We utilize online induction bright annealing technology in a hydrogen-reducing atmosphere. This process softens the cold-drawn tubes at 1050°C - 1150°C without scale formation, producing a bright, clean, and highly passive surface finish on both the inside and outside diameters.
Quality control is central to our manufacturing process. Every coil undergoes a series of physical tests, including mechanical compression, flaring, reverse bending, tensile properties, Rockwell hardness verification, and 100% pneumatic/air-tightness testing.
Liaocheng Sihe's precision seamless coiled tubes are deployed globally across demanding chemical, marine, energy, and high-purity sectors.
Continuous coiled loops reduce weld-induced flow restrictions and heat-affected zones, optimizing thermal transfer efficiency and durability under high thermal loads.
Seamless coiled lines prevent refrigerant leaks, maintaining closed-loop pressure and system efficiency in industrial cooling networks.
Corrosion-resistant alloys like Incoloy 825 and Duplex 2205 transport highly acidic reactants, chlorinated compounds, and oxidizing solutions securely.
Polished bright annealed 304 and 316L tubes prevent product buildup, simplify cleaning protocols, and maintain strict sanitary standards.
High-purity capillary tubing ensures precise liquid dosing and contamination-free transport of sensitive biological substances.
Used in superheater coils and high-pressure steam distribution paths to withstand high thermal stress and resist steam-side oxidation.
Ideally suited for downhole hydraulic control lines, subsea umbilical systems, and chemical injection valves in corrosive sour gas environments.
Precision control lines, structural fuel injection, exhaust feedback sensors, and hydraulic actuation tubes designed to withstand high vibration and pressures.
As offshore exploration transitions to ultra-deep reservoirs, infrastructure demands are shifting. We are actively engineering technical paths to meet these future requirements:
Developing thin-wall, high-strength super duplex lines that minimize deadweight on floating production storage and offloading (FPSO) units while maintaining pressure limits up to 15,000 psi.
Investigating specialized surface treatments to prevent hydrogen embrittlement. This is crucial for high-pressure delivery systems in the hydrogen fuel cell industry.
Integrating fiber optic cables into double-walled coiled tubing structures. This configuration enables real-time temperature, strain, and flow monitoring along the pipeline.
Liaocheng Sihe operates in compliance with international quality frameworks. Our production is certified under key global industrial regulatory structures.
We offer advanced processing options to deliver ready-to-install coiled components tailored to your design requirements.
We work with a wide range of materials (including 304, 316L, and Duplex 2205) and custom specifications, covering outer diameters from 6.35mm to 19.05mm and non-standard wall thicknesses.
Our processing capabilities include spiral coil forming, precision double-wall bending, and specialized multi-axis curvature formatting for compact heat exchangers.
We offer laser and mechanical cutting options to deliver accurate lengths with square, burr-free ends, ready for direct welding or orbital coupling.
We perform electro-polishing and chemical passivation to optimize corrosion resistance and surface smoothness for high-purity applications.
We supply pre-flanged, flared, or swaged end configurations compatible with standard compression fittings and high-integrity flange connectors.
Review our technical, commercial, and logistical guides. To request an updated pricelist for your specific project specifications, contact our engineering support team.
Review our selection of additional seamless coils, precision alloy pipes, and specialty options manufactured to meet rigorous quality standards.
