Sihe Steel
Sihe Steel
Explore our premium grade seamless coiled tubings engineered to meet rigorous international standards (ASTM, ASME, EN, JIS, GB).
In modern heavy industries, especially deepwater oil extraction, natural gas processing, and high-purity semiconductor manufacturing, standard jointed piping systems represent operational failure risks. Every weld joint is a potential site for pitting, stress corrosion cracking (SCC), and galvanic erosion.
The demand for stainless steel seamless coiled pipes has scaled dramatically. These products offer continuous lengths of up to 10,000 meters (32,800 feet) without a single orbital or longitudinal seam weld. By minimizing mechanical joinery, industrial networks achieve higher pressure thresholds, enhanced corrosion resistance, and simplified deployment procedures in subsea umbilical installations and control lines.
"According to metallurgical studies, seamless cold-drawn coiled pipes reduce fluid turbulence and friction losses compared to conventional welded alternatives. Our products operate reliably under environments surpassing 15,000 PSI."
Choosing the correct material chemistry determines performance under extreme chemical and structural loads.
Grades: 304/304L, 316L, 321, 317L, 309S, 310S
These standard alloys present excellent weldability, mechanical strength, and elevated resistance to atmospheric corrosion. Grade 316L utilizes lowered carbon parameters to minimize chromium carbide precipitation during hot environments.
Grades: Duplex 2205, Super Duplex 2507
Designed with a dual-phase microstructure consisting of austenite and ferrite. These alloys supply high yield strength (typically double that of austenitic alloys) and superior resistance to localized chloride pitting (PREN > 40 for 2507).
Grades: Incoloy 800, Incoloy 825, Inconel 625
Developed for extreme applications, particularly where hydrogen sulfide (H₂S), organic acids, or high chloride stresses exist. Ideal for deep offshore wells, downhole chemical dosing systems, and aerospace hydraulic assemblies.
| Property / Specification | Austenitic Series (e.g. 316L) | Duplex Series (e.g. 2205) | Nickel Alloy (e.g. Alloy 625) |
|---|---|---|---|
| Yield Strength (Rp 0.2, MPa) | Min. 220 | Min. 450 | Min. 410 |
| Tensile Strength (Rm, MPa) | 515 - 740 | 680 - 880 | Min. 825 |
| PREN (Pitting Resistance) | 23 - 25 | 34 - 36 | 45 - 52 |
| Primary Application | General Instrumentation & HVAC | Offshore Umbilicals & Geothermal | Deepwater HP Wells & Acid Gas |
| Online Bright Annealing | Standard Softening Treatment | Precise Phase-Control Quenching | Solid Solution Hardening Control |
Liaocheng Sihe Stainless Steel Material Ltd operates six production lines, featuring integrated online bright annealing technology. Bright annealing (BA) is performed in a highly controlled hydrogen-rich atmosphere. Unlike standard black annealing, which results in surface scaling that requires pickling, BA retains a highly reflective, smooth surface finish, optimizing interior corrosion resistance.
To ensure zero structural weaknesses across continuous 10,000-meter runs, every coil is subjected to a rigorous battery of non-destructive testing (NDT). We execute 100% pneumatic testing, hydraulic burst testing, hardness evaluations, flaring, flanging, and microstructural analysis. Our processes align with GB, ASTM, ASME, JIS, and EN requirements, ensuring safe application in petrochemical plants and subsea control systems.
Your strategic manufacturing partner for high-pressure, corrosion-resistant coiled tubing solutions.
Liaocheng Sihe Stainless Steel Material Ltd. has been specializing in the manufacturing and development of premium quality stainless steel sheets, polished tubes, and seamless coiled tubing for over 10 years. With three dedicated coiled tube lines out of our six production installations, we have established our presence as a globally recognized supplier.
Our products are trusted in more than 30 countries and regions worldwide, with 80% of our production exported directly to demanding industrial centers in the United States, Germany, Spain, South America, Southeast Asia, the Middle East, and Eastern Europe. We focus on matching precise dimensional tolerances with mechanical performance, allowing our partners to deploy equipment in deepwater oil exploration and high-purity semiconductor lines with absolute confidence.
Adding engineering value to our base alloy structures through custom downstream processes.
We process an array of materials including 304/L, 316L, and 2205 Duplex, with custom outer diameters ranging from 0.125 inches (3.175 mm) to 1 inch (25.4 mm) and wall thicknesses up to 0.165 inches (3 mm).
Includes complex spatial bending, continuous helical forming, and precision structural drawing tailored for integration within space-constrained high-performance heat exchangers.
We deploy precise laser cutting, clean mechanical shear-cutting, and automated high-linearity straightening to prepare coils for direct installation into sub-assemblies.
To reduce trace chemical contamination, we deliver high-purity chemical passivation, electro-polishing (EP), and mechanical polishing matching global semiconductor specs.
Precision tube end shaping and flanging processes. Ideal for integration with high-temperature engine exhausts, hazardous chemical transport, and aerospace fluid control.
Can design bespoke outer diameters, internal surface requirements, specific coil lengths, and unique wall thicknesses to meet custom project specifications.
Supporting high-performance infrastructure and manufacturing across multiple global industries.
Explore our main product lines designed for high-pressure fluid transfer and thermal management.
Available in grades 316L, 2205 Duplex, and Nickel Alloys. Features high dimensional precision and structural integrity under offshore conditions.
Optimized for rapid installation in geothermal arrays, district heat systems, and industrial utility operations.
Made from grade 310S and Incoloy 800. Maintains oxidation and creep resistance in furnaces and thermal reactors.
Optimized for subsea control lines and downhole injection pumps in active oil wells.
Ultra-smooth inside diameter (ID) values. Prepared to prevent particulate generation in gas systems.
Continuous length tubes up to 10,000 meters. Designed to support deep offshore energy platforms.
Dual-containment options for sensitive liquid-to-liquid heat exchange applications.
Duplex 2205 composition protects against high-chloride sea water pitting.
Micro-bore tubes for laboratory instrumentation and chromatographs.
Highly resistant to organic acids, sulfates, and alkaline environments.
Lightweight, high-strength tubing engineered for aerospace hydraulic controls.
Bespoke alloy combinations designed for high-stress geothermal systems.
Optimized for waste heat recovery loops in heavy process industries.
How technical developments in seamless coiled tubing support global decarbonization efforts.
As clean energy infrastructure expands, the transport of hydrogen gas presents unique metallurgical challenges. Hydrogen molecules are small enough to penetrate metal grain boundaries, which can cause hydrogen embrittlement. Embrittlement leads to micro-cracking and sudden structural failure, especially in high-pressure installations.
Liaocheng Sihe is researching alloy modifications to address these challenges. By controlling nickel and manganese ratios in our austenitic grades (e.g. 316L) and testing duplex formulations, we aim to produce coiled tubing that mitigates hydrogen embrittlement risks.
Geothermal energy extraction relies on piping that can withstand aggressive chemical attack from geothermal brines containing hydrogen sulfide, carbon dioxide, and chloride salts. Our Inconel 625 and Incoloy 825 seamless coiled tubes are designed for downhole heat exchangers in these environments. They resist high-temperature scaling and pitting corrosion, extending the service life of geothermal wells.
Technical guidance and commercial support for engineers and procurement managers.
Premium solutions for petrochemical, mechanical, and heavy-duty structural applications.
