Sihe Steel
Sihe Steel
High-precision seamless tubing and custom coils engineered for mission-critical applications worldwide.
Liaocheng Sihe Stainless Steel Material LTD is a premier global manufacturing pioneer specializing in high-grade stainless steel coiled tubes, polished precision tubes, and seamless coiled tubing. Armed with six fully integrated production lines, we execute strict compliance systems in alignment with the industry's most demanding production codes: GB, ASTM, ASME, JIS, and EN standards.
Our metallurgy portfolio covers standard austenitic classes such as 304/304L and 316L, high-temperature stabilization grades including 321, 317L, 309S, and 310S, alongside advanced super-alloys and duplex steels: Duplex 2205, Super Duplex 2507, Incoloy 825, Inconel 625, and INCOLOY 800.
With continuous investments in manufacturing facilities, we integrated the world’s leading online bright annealing technology. This enables online heat treatment at high temperatures to soften stainless steel tubing, maximizing flexibility, microstructural uniformity, and corrosion resistance.
Decoding mechanical properties, dimensional precision, and material integrity for heavy industrial applications.
In high-pressure and highly corrosive environments, structural failure is not an option. Unlike welded alternatives that feature a longitudinal weld seam—which acts as a localized site for potential stress concentration, micro-segregation, and galvanic corrosion—304 seamless steel tubes feature a completely uniform, solid steel structure. Formed via extrusion or rotary piercing, the absence of a seam yields superior pressure containment profiles and isotropic mechanical strength.
The 304 steel grade (equivalent to UNS S30400 or EN 1.4301) relies on a minimum chromium threshold of 18% and nickel levels of 8%. This precise chemistry forms a self-healing, microscopic chromium oxide passivation layer. In seamless executions, this barrier remains continuous and unblemished by the heat-affected zones (HAZ) common in welded joints. This guarantees sustained integrity when exposed to organic chemicals, acidic fluids, and cryogenic environments.
We supply seamless coiled tubing in continuous runs up to 32,800 feet (10,000 meters). This reduces orbital weld connections, lowering subsea installation costs and leak path risks.
Seamless design eliminates weld-line weaknesses. Our tubes handle high mechanical pressures, making them suitable for subsea umbilical control lines and hydraulic systems.
Bright annealing under controlled hydrogen-nitrogen atmospheres prevents carburization, ensuring consistent hardness values and high ductility for cold bending.
How raw material integration, local infrastructure, and technological economies of scale benefit global buyers.
China's global leadership in stainless steel manufacturing is rooted in complete industrial integration. At Liaocheng Sihe, we source raw materials from domestic mills, ensuring consistent metallurgical purity before processing begins. This direct supply chain shields global customers from volatile raw material price changes and ensures steady production schedules.
Additionally, our localized production footprint in Shandong Province links directly with major logistics hubs like Qingdao Port. This integration, combined with our 6 high-output extrusion and drawing lines, enables us to offer shorter lead times and competitive pricing without compromising quality.
Our facility operates 24/7 with a focus on yield optimization. By integrating bright annealing directly into the drawing process, we eliminate secondary handling. This keeps production costs down—savings we pass directly to our international procurement partners in the form of competitive, factory-direct quotes.
Every batch undergoes 100% pneumatic, hydrostatic, tensile, flaring, and hardness testing. Our in-house testing labs verify wall thickness tolerances within tight margins of ±0.05 mm, ensuring hassle-free onsite deployment.
We generate full Mill Test Certificates (MTC) conforming to EN 10204 3.1, detailing exact chemical compositions (carbon, manganese, phosphorus, sulfur, silicon, chromium, nickel) and verified tensile performance.
Our dedicated export division manages complex international shipping logistics, providing customs documentation, certificates of origin, and certified export packaging to protect coiled tubing during ocean transport.
Standard specifications, dimensional parameters, and customization limits.
| Dimensional & Material Parameter | Standard Specification Range | Custom Engineering Capabilities |
|---|---|---|
| Outer Diameter (OD) | 0.125 inch (3.175 mm) to 1.00 inch (25.4 mm) | Micro-precision calibration down to 0.5 mm for capillary applications |
| Wall Thickness (WT) | Up to 0.165 inch (3.0 mm) | Tolerances controlled down to ±0.02 mm upon engineering request |
| Continuous Coil Length | Standard lengths up to 32,800 feet (10,000 meters) | Orbital weld-free single continuous spans designed for subsea umbilicals |
| Available Steel Grades | 304, 304L, 316L, 321, 317L, 309S, 310S | Super Duplex 2507, Duplex 2205, Incoloy 825, Inconel 625, Incoloy 800 |
| Applicable Manufacturing Standards | GB/T 14976, ASTM A269, ASTM A312, ASME SA213, JIS G3459, EN 10216-5 | Custom testing and client-specified pressure testing |
| Surface Finishing Options | Bright Annealed (BA), Pickled & Annealed (AP), Mechanically Polished (MP) | Ultra-high vacuum cleaning and passivation for semiconductor applications |
Providing end-to-end fabrication services, reducing prep work for your onsite teams.
We support various materials (e.g., 304, 316L, 2205) and custom specifications, covering diameters from 6.35 mm to 19 mm, tailored to client layouts.
Our facility designs and forms custom spirals, tight-radius bends, and heat exchanger coils without distorting internal diameters.
Our drawing process shapes tubes to precise specifications, maintaining roundness and dimensional stability across production runs.
Using advanced laser and mechanical cutting lines, we deliver precise cut-to-length tubes with square, burr-free ends for automatic orbital welding.
We perform mechanical flanging and flaring for automotive exhaust connections, chemical manifolds, and industrial instrumentation joints.
Supplying mission-critical industries with high-performance seamless steel tubing.
Subsea Umbilicals and Oilfield Exploitation: As offshore exploration pushes into deeper waters, subsea umbilicals must withstand higher pressures, mechanical stresses, and corrosive seawater. Our ultra-long seamless coiled tubes in 316L, Alloy 825, and Duplex 2205 are designed to operate under high pressure without localized weld joint failures.
Semiconductor Gas and Chemical Distribution: The semiconductor industry relies on ultra-clean gas delivery. Our bright-annealed, high-purity seamless stainless steel tubes maintain smooth, contaminant-free inner surfaces, helping safeguard cleanroom environments.
Automotive Fuel, Brake, and Exhaust Systems: Automotive applications demand high fatigue resistance and thermal stability. Our JIS SUH409 welded tubes and 304/304L seamless options are engineered to withstand continuous engine vibration, heat cycling, and environmental exposure.
Clean Energy, Hydrogen, and Decarbonization: The energy sector is shifting toward green hydrogen storage and carbon capture. Our high-pressure seamless tubing offers low gas permeability and resists hydrogen embrittlement, supporting high-pressure hydrogen fueling and storage systems.
Liaocheng Sihe is committed to transparency, traceability, and strict quality standards.
Quality control at our facility is backed by third-party certifications and international compliance approvals. We maintain full traceability for all raw materials, from melt to finished tube.
Our quality management systems are regularly audited to ensure compliance with global standards, including pressure equipment directives and marine manufacturing certifications. This structural compliance ensures our materials are pre-approved for municipal, industrial, and subsea projects worldwide.
Get immediate answers regarding pricing structure, MOQ requirements, international compliance, lead times, and global shipping policies.
We manufacture a complete line of stainless steel and alloy tubes to meet diverse engineering specifications.
Our plant features advanced drawing and annealing systems to ensure consistent manufacturing quality.
Browse our full product range and request a quote for your specific project requirements.
