Sihe Steel
Sihe Steel
Engineered for severe environments. Direct access to our primary manufacturing inventory.
Industrial applications operating in deepwater wells, acid chemical reactors, or high-pressure systems require advanced materials to prevent stress corrosion cracking (SCC) and localized corrosion. Alloy 825 (UNS N08825) is a high-performance nickel-iron-chromium superalloy modified with additions of molybdenum, copper, and titanium. It offers an optimal balance of structural strength and corrosion resistance.
This technical whitepaper examines the metallurgy, fabrication techniques, and performance advantages of Alloy 825 precision tubing, produced by Liaocheng Sihe Stainless Steel Material LTD. We focus on critical application areas such as subsea control lines, downhole chemical injection systems, and heat exchangers.
| Element | Nickel (Ni) | Iron (Fe) | Chromium (Cr) | Molybdenum (Mo) | Copper (Cu) | Titanium (Ti) |
|---|---|---|---|---|---|---|
| Composition (%) | 38.0 - 46.0 | Balance (min 22.0) | 19.5 - 23.5 | 2.5 - 3.5 | 1.5 - 3.0 | 0.6 - 1.2 |
| Key Function | Resists chloride SCC | Structural base | Pitting/oxidation resistance | Resists crevice corrosion | Resists reducing acids | Stabilizes against sensitization |
The high nickel content provides resistance to chloride stress corrosion cracking, while the addition of molybdenum and copper offers durability in reducing environments containing sulfuric and phosphoric acids. The titanium addition stabilizes the alloy against intergranular corrosion during thermal exposures, maintaining weld-zone integrity.
Liaocheng Sihe Stainless Steel Material LTD operates six production lines and has ten years of manufacturing experience. We specialize in producing stainless steel coiled tubing, precision polished tubes, seamless coiled tubing, and extra-long pipes. Our production complies with ASTM, ASME, JIS, EN, and GB standards.
We process a wide range of materials, including standard austenitic grades, duplex, and nickel alloys:
304/304L, 316L, 321, 317L, 309S, 310S, INCOLOY 800
Duplex 2205 (UNS S31803), Super Duplex 2507 (UNS S32750)
Incoloy 825 (UNS N08825), Inconel 625 (UNS N06625)
Liaocheng Sihe has introduced online bright annealing technology. This process heat-treats the tubing under a controlled hydrogen atmosphere to eliminate surface oxidation, resulting in a clean, mirror-like inner and outer surface. It also ensures consistent ductility, which is essential for downhole installations and orbital welding.
As offshore oil and gas extractions move into deeper waters, severe subsea environments require high reliability. Alloy 825 coiled tubing is used in umbilical systems to connect offshore platforms to subsea production systems, carrying hydraulic control fluids, chemical treatments, and power lines.
To reduce risk, subsea systems require long, continuous tubing lengths without orbital welds. Liaocheng Sihe produces coiled tubing in sizes from 0.125 inch (3.175 mm) to 1 inch (25.4 mm) outer diameter, with wall thicknesses up to 0.165 inch (3.0 mm), and single coil lengths up to 32,800 feet (10,000 meters).
| Material Class | Pitting Index (PREN) | SCC Susceptibility | Acid Resistance | Primary Industrial Sector |
|---|---|---|---|---|
| Alloy 825 | 31.0 - 32.5 | Extremely Low | Excellent (Sulfuric / Phosphoric) | Offshore Umbilicals & DHSV Systems |
| Duplex 2205 | 34.0 - 36.0 | Low | Moderate | Flowlines & Manifold piping |
| Alloy 625 | 45.0 - 50.0 | Immune | Exceptional (Hydrochloric / Sour Gas) | Extreme Sour Service & Gas Lift Systems |
| SS 316L | 23.0 - 25.0 | High | Poor to Moderate | Instrumentation & General Processing |
Liaocheng Sihe offers custom metal fabrication, precision tube drawing, and assembly processes:
We support various materials (e.g., 304, 316L, 2205, 825) and specifications from 6.35mm to 19mm for stainless steel coils.
Our capabilities include bending, spiral forming, and precision drawing, designed for industrial heat exchangers.
We offer laser, mechanical, or flame cutting to achieve tight dimensional tolerances.
We develop surface finishing options, including bright annealing and precision mechanical polishing.
We offer end flanging for connections in automotive exhaust, chemical piping, and precision instrument lines.
We provide ultra-fine capillary tubing for instrumentation, sensors, chromatography, and control lines.
Duplex 2205 & Nickel 825 high fatigue tubing.
Continuous length tubing spooled on heavy-duty steel reels.
High-temperature furnace tubes and heater coils.
Precision tolerances for instrumentation systems.
Spliceless control lines for subsea well completions.
Electropolished ID for pharmaceutical applications.
Corrosion-resistant tubing for acidic media transport.
Designed for high-pressure subsea services.
Liaocheng Sihe Alloy 825 precision tubes are used in industries requiring resistance to high temperatures, high pressures, and chemical corrosion:
Liaocheng Sihe implements testing and inspection procedures on our six production lines. Testing capabilities include flaring, bending, tensile testing, 100% hardness inspection, air tightness testing, and hydrostatic testing to ensure zero defect rates.
Our products are certified by international inspection organizations and comply with ASTM/ASME standards for high-pressure applications:
The company has exported its products to more than 30 countries and regions, including the United States, Germany, Spain, South America, Southeast Asia, the Middle East, and Eastern Europe. Approximately 80% of our production volume is exported globally, supported by secure packaging, timber/steel reels, and complete material certification.
Modern process plants and offshore wells operate under increasingly severe conditions. Liaocheng Sihe is continually upgrading its metallurgy and fabrication techniques to support new industrial demands:
We are developing advanced gas tungsten arc welding (GTAW) methods to produce continuous, weld-free coiled tubing lines longer than 12,000 meters for deepwater operations.
We are optimizing our bright annealing and drawing techniques to reduce inside diameter surface roughness (Ra < 0.4 μm), lowering pressure drops and turbulence.
We are adjusting cold-drawing parameters to increase the yield strength of our Alloy 825 and 625 lines, helping them withstand hydrostatic pressures in deepwater environments.
Answers to technical and commercial inquiries regarding our Alloy 825 precision tubes.
Our prices depend on raw material costs, size requirements, and purchase volumes. Please contact us with your specifications, and we will send you an updated pricelist.
Yes, we require all international orders to meet a minimum order quantity. For smaller quantities or trial orders, please contact our sales department to check available stock.
Yes, we provide standard documentation, including Mill Test Certificates (MTC to EN 10204 3.1), Certificates of Conformance, insurance documentation, Certificates of Origin, and custom packaging lists.
For stock samples, the lead time is approximately 7 days. For mass production run cycles, the lead time is 20 to 30 days after receiving the deposit payment. Lead times begin once we have received the deposit and finalized technical drawings.
We accept bank wire transfers (T/T), Western Union, and PayPal. Our standard term is a 30% deposit in advance, with the 70% balance due against the copy of the Bill of Lading (B/L).
We warrant our materials, workmanship, and dimensional compliance. Our goal is customer satisfaction. If any quality issue arises, we will work with you to resolve it.
Yes, we use heavy-duty export packaging, including wooden crates, steel spools, and protective wrapping. This ensures the tubing remains undamaged and free from contamination during ocean transit.
Shipping costs depend on the delivery location, transport mode, and cargo weight/volume. Air express is fastest but more expensive; ocean freight is the most cost-effective solution for large volumes. We can provide shipping quotes once order details are finalized.
Factory-direct steel solutions, high-grade alloys, and custom coiled tubing.
