Sihe Steel
Sihe Steel
Explore our leading product range covering capillary tubes, coiled tubing, heat exchanger pipes, and custom grades engineered to global standards.
In modern industrial engineering, choice of fluid conveyance channels dictates overall facility lifespan, process security, and hazard containment. Seamless stainless steel pipes and tubes constitute the primary barrier against high pressures, extreme temperatures, and chemical attack. Far from simple structural conduits, these high-tech components are designed to withstand corrosion in challenging onshore and offshore conditions.
This technical guide, provided by Liaocheng Sihe Stainless Steel Material LTD, analyzes the metallurgical formulations, processing mechanics, testing methods, and pricing variables that global purchasing teams must evaluate when sourcing seamless stainless steel coiled tubing and capillary pipes. Our emphasis is on aligning raw material selection with application conditions to optimize cost and performance.
Core Focus: Selecting the correct Corrosion Resistant Alloy (CRA)—such as Duplex 2205, Inconel 625, or Incoloy 825—minimizes risk, avoids costly shutdowns, and ensures safety in harsh offshore applications.
While welded tubing is suitable for cosmetic or low-pressure structural installations, high-reliability systems in the chemical, aerospace, and energy sectors require seamless designs. This is because the welding process alters the metal's grain structure:
Established as a key manufacturer in China, Liaocheng Sihe Stainless Steel Material LTD operates six advanced cold drawing and cold rolling production lines. We specialize in producing stainless steel coiled tubing, precision capillary tubes, and heat exchanger piping, complying with strict international standards: GB, ASTM, ASME, JIS, and EN.
Our manufacturing capabilities cover a wide range of materials and sizes to meet demanding industrial needs, especially for deepwater subsea control lines, hydraulic instrumentation, and chemical injection systems.
Using vertical integration and bright hydrogen annealing, we produce exceptionally long coils. This reduces the need for orbital orbital welds on-site, decreasing potential failure points and installation costs in subsea installations.
Take a closer look at our production facilities, quality inspection processes, and primary product lines at Liaocheng Sihe.
Precise monitoring of cold drawing lines
Inline atmospheric furnace treating coiled tubes
Duplex 2205 high-strength tubing
Widely used in offshore oil & gas control systems
Designed for severe kiln and furnace components
Dimensional control of thin wall pipes
Pre-shipment inspection on dedicated drums
Pre-forming for complex heat exchangers
Designed for high hydrogen sulfide sour service environments
Ready for integration into marine umbilicals
Achieving low roughness averages (Ra)
Verifying structural integrity up to rated limits
100% electromagnetic scan for surface defects
Ultra-fine diameter pipes for chromatography
Reinforced steel reels protected with geotextiles
Choosing the correct alloy involves balancing corrosive exposure (chlorides, hydrogen sulfide, carbon dioxide, low/high pH acids) with mechanical loads and temperature limits. Here is a technical breakdown of typical CRA options:
| Alloy Grade | UNS / EN Designation | Key Chemical Components | PREN* | Primary Industry & Application |
|---|---|---|---|---|
| AISI 316L | UNS S31603 / 1.4404 | Cr: 16-18%, Ni: 10-14%, Mo: 2-3%, C: ≤ 0.03% | ~23-25 | General chemical processing, biopharm, marine instrumentation. |
| Duplex 2205 | UNS S32205 / 1.4462 | Cr: 22-23%, Ni: 4.5-6.5%, Mo: 3-3.5%, N: 0.14-0.2% | ~35 | Oil & Gas subsea downhole, high-chloride heat exchangers. |
| Super Duplex 2507 | UNS S32750 / 1.4410 | Cr: 24-26%, Ni: 6-8%, Mo: 3-5%, N: 0.24-0.32% | >40 | Deepwater subsea umbilicals, desalination plants, SWRO pumps. |
| Incoloy 825 | UNS N08825 / 2.4858 | Ni: 38-46%, Cr: 19.5-23.5%, Mo: 2.5-3.5%, Cu: 1.5-3% | ~31 | Acid gas wells, oil refinery piping, radioactive waste disposal. |
| Inconel 625 | UNS N06625 / 2.4856 | Ni: ≥ 58%, Cr: 20-23%, Mo: 8-10%, Nb+Ta: 3.15-4.15% | ~50 | High-pressure offshore drilling, exhaust structures, aerospace manifolds. |
*Pitting Resistance Equivalent Number (PREN) = %Cr + 3.3(%Mo + 0.5%W) + 16%N. Higher values indicate greater resistance to localized pitting in chloride-rich environments.
In offshore and marine applications, seawater exposure presents a constant pitting risk. Standard 304 or even 316L steels can experience rapid pitting and crevice corrosion under biofilms or salt crusts. Upgrading to Duplex 2205 or Super Duplex 2507 provides a solution due to their balanced ferrite-austenite microstructures. These materials offer both high yield strength (typically twice that of standard austenitics) and excellent resistance to chloride-induced stress corrosion cracking (SCC).
Our seamless products are utilized across demanding commercial and heavy industrial fields worldwide. Each application presents unique engineering requirements.
Optimized thin-wall coiled configurations for maximum thermal conductivity and corrosion resistance.
High pressure limits for modern synthetic and natural refrigerants.
Conveyance lines for aggressive acids, organic solvents, and caustic compounds.
Clean inner diameters ensuring sanitary operation, compliant with FDA guidelines.
Electropolished capillary lines for ultra-pure water distribution systems.
Superheater loops and steam generator tubes operating under extreme temperatures.
Catalytic cracker feeds and processing piping subject to sulfidation and carburization.
Hydraulic brake and instrumentation lines requiring tight bending tolerances and high pressure limits.
Our commitment to product reliability is backed by systematic testing at each phase of production. We provide comprehensive material documentation, including mill test reports (MTR) according to EN 10204 3.1, certificates of origin, and compliance summaries.
Beyond producing raw seamless tubes, Liaocheng Sihe offers specialized custom fabrication services:
Our factory processes are certified by national and international bureaus, demonstrating our focus on product quality and manufacturing standards.
Procuring seamless stainless steel tubing requires balancing upfront unit costs with long-term reliability. A low initial price point can lead to high operating costs if a tube fails in service, highlighting the importance of evaluating Total Cost of Ownership (TCO).
The industrial piping sector is shifting toward materials with lower carbon footprints and higher efficiency. Hydrogen production and carbon capture (CCUS) projects require tubing that can withstand embrittlement and high-pressure carbon dioxide service. Liaocheng Sihe is researching advanced alloy compositions and optimized heat treatments to support these energy transition applications.
Common questions from design engineers, procurement heads, and EPC project managers regarding our operations and products.
Browse our complete catalog of industrial tubing, sheets, and capillary lines designed for high-stress applications.
