Sihe Steel
Sihe Steel
Discover our high-precision seamless and welded tube portfolio, engineered for offshore control units, high-temperature heat exchangers, and precision instrumentation applications.
Liaocheng Sihe Stainless Steel Material LTD is a world-class manufacturer specializing in high-grade stainless steel coiled tubes, precision polishing tubes, and seamless capillary tubing systems. Boasting six state-of-the-art production lines, we enforce strict compliance with major international standards including GB, ASTM, ASME, JIS, and EN. Our material catalog encompasses highly demanding alloys suited for extreme operational stress: 304/304L, 316L, 321, 317L, 309S, 310S, and INCOLOY 800, alongside specialized grades such as Duplex 2205, Super Duplex 2507, Incoloy 825, and Inconel 625.
Our specialized product configurations range in outer diameter from 0.125 inches (3.175 mm) to 1 inch (25.4 mm), with wall thicknesses reaching up to 0.165 inches (3 mm). To facilitate efficient subsea umbilical manufacturing and deep-well operations, we are capable of delivering continuous, weld-free coiled tubing in lengths up to 32,800 feet (10,000 meters).
By introducing world-class online bright annealing technology, we perform real-time structural softening of stainless steel pipes in a pure hydrogen protective atmosphere. This completely eliminates internal stresses and oxidation, generating a high-precision, mirror-smooth surface with superior mechanical ductility.
To guarantee total reliability, our testing facility carries out complete mechanical validations: flattening, flaring, micro-hardness (100%), tensile strength, hydrostatic pressure, and pneumatic air tightness testing. It is this technological rigor that makes us the choice supplier for critical systems across 30+ countries.
Choosing the right grade of corrosion-resistant alloy is critical to minimizing stress corrosion cracking (SCC) and pitting in chloride-rich environments. The "L" in 316L denotes a low carbon content (restricted to ≤0.03%), which prevents chromium carbide precipitation along grain boundaries during welding—commonly referred to as sensitization.
| Material Grade | Carbon (C) % | Chromium (Cr) % | Nickel (Ni) % | Molybdenum (Mo) % | PREN (Pitting Resistance Equivalent) |
|---|---|---|---|---|---|
| AISI 304 | ≤0.08 | 18.0 - 20.0 | 8.0 - 10.5 | - | ~ 18.0 |
| AISI 316L | ≤0.03 | 16.0 - 18.0 | 10.0 - 14.0 | 2.00 - 3.00 | 23.0 - 25.0 |
| Duplex 2205 | ≤0.03 | 21.0 - 23.0 | 4.5 - 6.5 | 2.50 - 3.50 | 34.0 - 36.0 |
| Incoloy 825 | ≤0.05 | 19.5 - 23.5 | 38.0 - 46.0 | 2.50 - 3.50 | 31.0 - 33.0 |
In offshore oil and gas extraction, sea salt spray and dissolved chlorides degrade standard austenitic stainless steels rapidly. Molybdenum addition in 316L alters the passive chromium oxide protective layer, providing high resistance to local pitting attack. When operations step up into ultra-deep offshore systems, Sihe Steel provides upgraded materials, transitioning smoothly to Duplex 2205 or Incoloy 825 where higher pressure limits and severe sour gas (H2S) parameters exist.
Our drawing benches operate with tight tolerance control. Continuous laser micrometer feedback keeps dimensional variation within ±0.02mm, yielding ultra-clean inner walls for fluid chromatography and semiconductor gas pipelines.
Continuous furnace heat treatment up to 1050°C under pure dry hydrogen atmosphere prevents any micro-scale surface oxidation. The pipe retains its metallic luster, eliminating acid pickling requirements.
Every single batch undergoes hydrostatic pressure tests up to 70 MPa alongside online electromagnetic eddy current inspection to check for sub-surface anomalies, guaranteeing zero leakage over miles of installation.
Conventional orbital joints represent potential failure zones under high stress and chemical degradation. Through advanced metallurgy and drawing processes, we can manufacture coiled tubes up to 10,000 meters in a single continuous segment.
This capability optimizes the manufacturing layout for subsea electro-hydraulic control lines (umbilicals) by reducing intermediate splices and welding overheads, maximizing safety in ultra-deepwaters.
Our custom-engineered tubing portfolio delivers critical performance metrics across diverse demanding industrial sectors.
Designed with optimized thermal transfer properties and high vibration stability for chemical refining boilers.
Offers low corrosion risk under moisture-rich conditions using specialized seamless coiled layouts.
Perfect acid and alkali resilience using 316L and Inconel 625 alloys for aggressive medium delivery.
Smooth interior diameters to prevent bacterial colonization, meeting rigorous sanitary safety profiles.
Electro-polished high-purity capillary pipes for chemical transfer and precise diagnostic instruments.
High thermal fatigue resistance for steam lines and condenser elements under extreme temperature cycles.
Resistant to high H2S concentrations, ideal for downhole control lines and gas injection tubing.
Precision hydraulic line networks that tolerate extreme pressures, vibrations, and thermal shocks.
We go beyond standard extrusion to deliver ready-to-install custom component solutions.
Supports all major alloy materials (304, 316L, 2205) and custom sizes (diameter 6.35mm to 19mm) for stainless steel coiled tubing arrays.
Techniques include tight-radius bending, spiral-wound formation, and high-precision structural drawing to optimize performance in compact heat exchangers.
Features clean laser, mechanical, or flame cutting options to minimize deformation, preparing the pipe for immediate site fabrication.
Electro-polishing (EP) and mechanical polishing treatments meet cleanroom specifications for gas-delivery setups.
Specialized end profiling for secure couplings in automotive exhaust connections and chemical system piping.
Our engineering department designs to custom prints.
Our quality management systems are fully certified. We offer complete heat trace documentation and third-party inspection clearances for safety-critical pipelines.
As heavy industries shift toward decarburization and clean energy systems, critical piping must evolve. Hydrogen transmission pipelines represent a core sector where material integrity is under scrutiny. 316L stainless steel, with its robust FCC (face-centered cubic) lattice and stable austenitic phase, offers solid resistance to hydrogen embrittlement. We are expanding our production capability to refine the internal surface roughness of tubes below Ra 0.25 μm, preventing hydrogen micro-crack initiation under extreme pressures.
Furthermore, our engineering teams are developing carbon-offset manufacturing lines. By integrating intelligent thermodynamic controls in our online bright annealing furnaces, we reduce energy consumption by 15% per metric ton. This approach addresses the tightening Carbon Border Adjustment Mechanism (CBAM) requirements in the EU and North America, ensuring our global supply chain remains competitive and green-compliant.
We offer customized solutions for high-performance projects, including high-temperature 310 series stainless steels and corrosion-resistant duplex alloys.
