Sihe Steel
Sihe Steel
Explore our industrial range of precision-manufactured coiled and straight duplex tubing designed to withstand high chloride concentrations and corrosive environments.
Liaocheng Sihe Stainless Steel Material Ltd
Established as an industry benchmark in China, we manage six state-of-the-art production lines dedicated exclusively to the high-tolerance manufacturing of stainless steel coiled tubes, polishing pipes, and seamless control lines. Working strictly to GB, ASTM, ASME, JIS, and EN standards, our engineering department ensures every production batch conforms to the tightest dimensional and metallurgical standards required by safety-critical sectors.
Our metallurgy portfolio is comprehensive, offering specialized solutions in Austenitic steels (304/304L, 316L, 321, 317L, 309S, 310S), high-performance nickel superalloys (INCOLOY 800, Incoloy 825, Inconel 625), and optimized biphasic microstructure alloys (Duplex 2205, Super Duplex 2507). Designed for reliability, our seamless coiled configurations scale from small diameters to long lengths up to 32,800 feet (10,000 meters), drastically reducing orbital welding requirements for subsea oil and gas extraction plants.
By implementing online bright annealing technology, we control grains distribution and phase ratios directly during the fabrication cycle. Our continuous investment in material science allows us to support leading industries globally, shipping more than 80% of our production to over 30 countries across the US, Germany, Spain, South America, Southeast Asia, the Middle East, and Eastern Europe.
Advanced Production Lines
Max Continuous Length
Exporting Countries
NDT & Tightness Tested
Deep-dive into the mechanical, physical, and chemical attributes that make UNS S31803 / S32205 the gold standard for high-performance thermal transfer equipment.
Duplex 2205 features a biphasic crystal layout containing approximately 50% ferrite and 50% austenite. This specific balance imparts double the yield strength of conventional 316L, alongside a vastly superior resistance to localized pitting and stress corrosion cracking (SCC) in hot brine loops.
With a Chromium content of 22%, Molybdenum at 3.2%, and Nitrogen optimized at 0.18%, the Pitting Resistance Equivalent Number (PREN = Cr% + 3.3Mo% + 16N%) of 2205 duplex typically exceeds 35, proving its integrity in seawater chemical treatment cells and acidic gas lines.
Exhibiting high thermal conductivity (19.0 W/m·K at 100°C) and low coefficient of thermal expansion, Duplex 2205 minimizes localized thermal stress in exchangers, reducing mechanical fatigue failures and prolonging structural life in power generation blocks.
| Alloy Grade | UNS Number | Cr (%) | Ni (%) | Mo (%) | N (%) | Yield Strength (MPa) | Tensile Strength (MPa) |
|---|---|---|---|---|---|---|---|
| Duplex 2205 | UNS S31803 / S32205 | 21.0 - 23.0 | 4.5 - 6.5 | 2.5 - 3.5 | 0.08 - 0.20 | ≥ 450 | ≥ 620 |
| Super Duplex 2507 | UNS S32750 | 24.0 - 26.0 | 6.0 - 8.0 | 3.0 - 5.0 | 0.24 - 0.32 | ≥ 550 | ≥ 750 |
| Austenitic 316L | UNS S31603 | 16.0 - 18.0 | 10.0 - 14.0 | 2.0 - 3.0 | ≤ 0.10 | ≥ 170 | ≥ 485 |
Sihe Steel utilizes integrated smart fabrication workflows that combine mechanical precision drawing with online inert gas protection systems. The key process that differentiates our pipes is our World-Class Online Bright Annealing Technology. Continuous processing under pure hydrogen atmosphere removes internal stresses, preventing carbide sensitization without oxidating the pipe's interior and exterior surfaces.
To assure absolute safety in deep ocean oil lines and petrochemical processes, we implement strict destructives and non-destructive testing (NDT):
From complex custom bending projects to advanced surface finishes, we supply end-to-end processing solutions to deliver field-ready tubes directly to your project site.
Precise dimensions with custom wall thicknesses (up to 3.0mm) and outer diameters (3.175mm to 25.4mm) customized to print specifications.
High-precision spiral forming, serpentine configurations, and tight-radius coiling loops designed for high-efficiency heat exchangers.
Burr-free laser and mechanical cutting to custom pre-cut lengths, avoiding mechanical deformation of pipe ends.
Electropolishing, mechanical polishing, and chemical pickling to obtain clean, passive inner walls preventing fouling.
Controlled hydraulic flanging and cold-forming to prepare the tubes for secure automotive and industrial manifold coupling.
Deploying reliable tubing systems across critical global sectors operating under extreme temperature gradients, mechanical loads, and corrosive conditions.
As the demand for deepwater exploration (depths greater than 3,000 meters) intensifies, heat exchanger components encounter higher pressures, lower temperatures, and elevated chloride levels. Sihe Steel is adapting its technical roadmap to support the next generation of industrial infrastructure:
Global regulations demand high safety and lower carbon emissions. By replacing traditional single-phase austenitic steels (like 304 or 316) with Duplex 2205, companies can reduce raw material consumption by up to 35% thanks to its high yield strength (which allows for thinner tube walls). This reduction directly lowers shipping weight and overall carbon emissions in construction.
Furthermore, Sihe Steel is committed to complying with RoHS and REACH regulations, avoiding the use of hazardous chemicals in surface treatment stages. We support clients with complete material origin tracking, ensuring full traceablility from raw ladle analysis to final delivery.
Our comprehensive production program targets specialized metal tubing configurations across varying material grades and shapes.
Highly resistant 2205 duplex coils for petrochemical processing, subsea control lines, and industrial heat exchangers.
Precision 1/2-inch and 3/8-inch bright annealed coiled tubes for instrumentation and process control loops.
Oxidation-resistant heat exchanger tubes built specifically to survive cyclic heating operations up to 1100°C.
Straight and bent heat exchanger tubes engineered to prevent localized crevice corrosion and pitting.
Extremely tight tolerance capillary pipes for surgical instruments, chromatography, and automotive sensors.
Alloyed with high molybdenum and chromium to resist heavy sulfuric and phosphoric chemical environments.
Premium grade nickel-iron-chromium alloys designed to resist stress corrosion cracking and pitting in acid gas.
Industrial sheets for heat exchanger baffles, pressure vessel shell plating, and structural welding assemblies.
Clean bore mirror-polished surface tubes designed for sterile fluid handling in food and pharmaceutical plants.
Corrosion resistant welded tubing for marine wet exhausts and automotive heat-insulating manifolds.
Compact cooling coils for HVAC evaporators, chillers, and subsea geothermal heat capture blocks.
Seamless clean lines optimized for hydraulic fluid power networks in aviation and offshore structures.
Liaocheng Sihe is ISO audited and certified by major classification societies to guarantee our materials are fully approved for high-pressure systems.
Expert answers addressing the logistical, commercial, and technical specifications of our duplex 2205 heat exchanger pipe solutions.
Our pricing is subject to periodic adjustments based on raw alloy material prices (Nickel, Molybdenum, Chromium) and energy costs. Please contact our sales office with your exact specifications, and we will send an updated price list within 24 hours.
For international shipments, we require an ongoing minimum order quantity depending on custom sizes. If you need smaller trial quantities for prototype testing or localized engineering, please check our standard stock availability list.
We provide comprehensive certification folders, including EN 10204 3.1 Mill Test Certificates (MTC), Certificates of Conformity (CoC), mechanical test results (tensile, hardness, flattening), non-destructive testing reports, and Certificates of Origin (CO) for export clearance.
Custom or prototype samples take approximately 7 days. For mass production runs, the standard lead time is 20-30 days after receipt of down payment and final engineering approval. Contact our sales department to expedite urgent offshore shutdown requirements.
We generally accept Bank Telegraphic Transfers (T/T): 30% deposit in advance to initiate production, and the remaining 70% balance paid against the copy of the Bill of Lading (B/L). We also accept Western Union and PayPal for small sample runs.
We warrant our materials against manufacturing and chemical defects. It is our corporate culture to address and resolve any material non-conformity immediately. We offer testing support to ensure absolute satisfaction on site.
We use heavy-duty export packaging, including wooden crates, steel frames, and custom spooling cores for coiled tubing to prevent deformation during sea freight. Specialized air-tight vacuum packaging or moisture protection is available upon request.
Shipping costs depend on weight, volume, destination, and the chosen transport mode (Sea freight, Air freight, or Express courier). Exactly calculated logistics quotes can be provided once you supply details of order volume and destination port.
Explore our secondary line of specialized materials, including heat exchanger plate stock and high-alloy exhaust tubes.
