Sihe Steel
Sihe Steel
Welcome to Liaocheng Sihe Stainless Steel Material LTD. Established in China as a premier engineering leader, we operate six state-of-the-art production lines specialized in producing premium-grade stainless steel coiled tubes, precision polishing tubes, and seamless instrumentation piping.
We adhere strictly to international manufacturing standards including GB, ASTM, ASME, JIS, and EN. Our manufacturing capabilities bridge complex material specifications with demanding mechanical requirements. We ensure that every millimeter of our piping can withstand harsh operations in maritime, petrochemical, aerospace, and energy fields.
Whether your application demands classic corrosion-resistant alloys or super-duplex grades designed for subsea conditions, Liaocheng Sihe is your certified partner for seamless piping solutions.
In modern heavy industries, the demand for seamless stainless steel pipes and coiled tubing has shifted from generic transport solutions to highly specific, life-cycle critical engineering components. Seamless construction completely avoids longitudinal weld seams, offering uniform mechanical properties that are crucial in high-pressure, cryogenic, and highly corrosive operating environments.
As international oil and gas extractions plunge into deeper waters, environments become exponentially more hostile. Subsea control panels, chemical injection lines, and umbilical links must withstand extreme pressures and corrosive chemistries. High-alloy materials such as Duplex 2205, Super Duplex 2507, and nickel alloys like Incoloy 825 and Inconel 625 are essential for these systems.
Liaocheng Sihe manufactures seamless coiled tubing in continuous, extra-long runs reaching up to 32,800 feet (10,000 meters) without orbital welds. This decreases installation times, simplifies logistics, and removes potential leak points.
A key factor in Liaocheng Sihe's product quality is our online bright annealing (BA) process. Standard hot rolling and annealing leave a dark oxide scale that requires acid pickling, which can roughen surfaces. Bright annealing uses a highly controlled hydrogen-rich gas mixture. This reduces oxides and yields a clean, smooth, reflective finish on both internal and external walls.
Our post-annealing quality program includes multiple testing methods to guarantee reliability:
Pressure tests verify wall integrity and ensure leak-free performance under pressure.
Flaring, bending, and compression testing verify high ductibility and yield strength.
Ensures consistent microstructural composition across long continuous coil runs.
Non-destructive electromagnetic scans detect subsurface flaws along the tube wall.
| Steel Grade & Alloy Classification | UNS / Standard Designator | Key Performance Features | Typical Applications |
|---|---|---|---|
| Austenitic 304 / 304L | UNS S30400 / S30403 | Excellent ductility, weldability, and corrosion resistance under general exposure. | General HVAC, food & beverage, structural support, auto parts. |
| Austenitic 316 / 316L | UNS S31600 / S31603 | Molybdenum content provides strong resistance to chloride-induced pitting. | Chemical equipment, heat exchangers, marine instrumentation, biotech. |
| Austenitic 321 | UNS S32100 | Titanium-stabilized to prevent intergranular corrosion at high temperatures. | Aerospace components, exhaust systems, boiler components. |
| Duplex 2205 | UNS S31803 / S32205 | Dual-phase structure yields high yield strength and resistance to stress corrosion cracking. | Subsea umbilical tubing, chemical processing vessels, desalination. |
| Super Duplex 2507 | UNS S32750 | Pitting Resistance Equivalent Number (PREN) > 40, high mechanical strength. | Deep-water offshore oil & gas extraction, corrosive brine handling. |
| Incoloy 825 | UNS N08825 | Nickel-iron-chromium base resistant to sulfuric and phosphoric acids. | Oil & gas downhole control lines, chemical acid distribution systems. |
| Inconel 625 | UNS N06625 | Nickel-chromium-molybdenum alloy resistant to oxidation and carburization at high temperatures. | Aerospace ducting, marine exhaust stacks, high-temp heat exchangers. |
Our sizing capabilities are broad. Coiled tubing is available in outer diameters ranging from 0.125 inches (3.175 millimeters) up to 1 inch (25.4 millimeters), with wall thicknesses up to 0.165 inches (3 millimeters). Liaocheng Sihe also provides customization options, allowing you to tailor wall thickness, outer diameters, and lengths to your specific engineering requirements.
Supports various materials (e.g., 304, 316L, 2205) and specifications (diameter 6.35mm to 19mm) for stainless steel coils.
Includes bending, spiral forming, precision drawing, and other processes tailored for heat exchangers.
Laser cutting, mechanical cutting, or flame cutting for high-precision and efficient material processing.
We devote ourselves to developing new products with state-of-art technologies, providing bright annealing and mechanical polishing.
Used in automotive exhaust systems, chemical pipelines, and precision instrument connections to secure high-integrity seals.
At Liaocheng Sihe, we enforce strict tracebility controls from raw material melting down to final packaging. Our laboratory features specialized testing equipment to monitor dimensional tolerances, chemical compositions, and mechanical capabilities.
We maintain quality certifications to meet international compliance standards for global project sites. Below is a portfolio of our manufacturing licenses and compliance certificates:
