Sihe Steel
Sihe Steel
Explore our factory-direct stainless steel seamless pipes, capillary tubes, and sheets engineered for severe operational environments.
In global industrial fluid dynamics, 304 Stainless Steel Seamless Pipe is widely recognized as a foundational material for high-pressure, thermal-intensive, and corrosive environments. Unlike welded pipes, which contain a metallurgical heat-affected zone (HAZ) along the weld seam, seamless pipes are extruded and drawn. This process yields a uniform austenitic grain structure throughout the cross-section, eliminating localized stress concentrations and preventing stress corrosion cracking (SCC) in harsh environments.
Compliant with ASTM A312 / ASME SA312 standards, our seamless pipes feature a robust chemical composition of 18-20% Chromium and 8-10.5% Nickel. This ratio creates a stable chromium oxide (Cr₂O₃) passive layer that resists oxidation in temperatures up to 870°C (1600°F).
Engineered to meet specific mechanical requirements across distinct high-stress industrial applications.
Extracted oil and gas operations require umbilical coiled tubing that can withstand up to 10,000 meters of continuous installation. By using 304, 316L, Duplex 2205, and Super Duplex 2507 alloys, our tubing resists chloride pitting and structural fatigue from deep-sea currents.
Ultra-high purity (UHP) gas delivery networks require internally polished, seamless stainless steel tubing. Bright annealing keeps the inner surface roughness (Ra) under 0.25 μm, preventing particle entrapment and catalytic reactions during wafer production.
Closed-loop geothermal heat exchangers require seamless coiled tubing that can withstand mechanical pressure variations and soil corrosion without leaking. Our customized continuous coil length significantly reduces underground joint connections, lowering leak risks.
Driving engineering innovations through advanced metallurgy, precision manufacturing, and clean heat treatments.
Treating stainless steel in a protective atmosphere of hydrogen and nitrogen at temperatures up to 1050°C prevents carbon precipitation. This process yields a clean, scale-free surface that does not require additional pickling.
Multi-pass cold-drawing on high-precision mandrels controls outside diameter (OD) and wall thickness (WT) tolerances to within ±0.05 mm, improving structural uniformity for demanding subsea umbilical lines.
We use eddy current testing (ECT), hydrostatic pressure testing, and chemical composition checks (PMI) to ensure our products perform reliably under high operating pressures.
Liaocheng Sihe Stainless Steel Material Ltd operates from Liaocheng, Shandong, a major steel hub in China. This location provides convenient access to high-grade raw materials and efficient logistics networks.
Our facility integrates the entire production process—from billet raw materials to precision drawing, cold-rolling, inline bright annealing, and spool winding. This vertical integration allows us to keep lead times to 20-30 days for volume orders, compared to the industry average of 45-60 days.
By managing production and testing internally, we maintain competitive pricing without compromising on quality standards. This setup has enabled us to export 80% of our products to over 30 countries and regions, including the US, Germany, Spain, South America, Southeast Asia, the Middle East, and Eastern Europe.
From precision drawing to specialty profile bending, we configure stainless steel alloys to meet custom specifications.
We support custom manufacturing for 304, 304L, 316L, and Duplex 2205 alloys, with outer diameters (OD) ranging from 6.35 mm to 19 mm for coiled tubing applications.
Our facility produces continuous, orbitally weld-free coiled tubing in lengths up to 32,800 feet (10,000 meters), designed for subsea umbilical control systems.
We supply specialized end-forming, including flanging and flares, for automotive exhaust systems, chemical pipelines, and precision instrumentation fittings.
Where our high-performance tubing and sheet products are installed in critical systems.
Liaocheng Sihe manufactures in strict accordance with ASTM, ASME, JIS, EN, and GB production standards. Each production run is fully documented and traceable from raw melt to final product.
We provide standard documentation, including Material Test Certificates (MTC) conforming to EN 10204 3.1, Certificates of Analysis (CoA), and third-party inspection approvals.
Download Compliance Catalog
Technical reference for engineers designing systems with stainless steel piping and capillary tubing.
| Steel Grade Designation | Carbon (Max %) | Chromium (%) | Nickel (%) | Tensile Strength (Min MPa) | Elongation (%) |
|---|---|---|---|---|---|
| 304 / UNS S30400 | 0.08 | 18.0 - 20.0 | 8.0 - 10.5 | 515 | 35 |
| 304L / UNS S30403 | 0.03 | 18.0 - 20.0 | 8.0 - 12.0 | 485 | 35 |
| 316L / UNS S31603 | 0.03 | 16.0 - 18.0 | 10.0 - 14.0 | 485 | 35 |
| Duplex 2205 / UNS S32205 | 0.03 | 22.0 - 23.0 | 4.5 - 6.5 | 655 | 25 |
Technical answers regarding material properties, logistics, processing limits, and procurement.
The pressure rating depends on the wall thickness, outer diameter (OD), and design temperature, calculated using Barlow's Formula: P = 2St / D. For example, a 1/2" OD seamless pipe with a 0.049" wall thickness can operate at pressures exceeding 4,500 PSI (310 Bar) under ambient temperatures, maintaining a 4:1 safety factor.
Bright annealing is performed in a hydrogen/nitrogen atmosphere. This process keeps chromium dissolved in the steel matrix rather than forming chromium carbides at the grain boundaries (sensitization). The result is improved resistance to intergranular corrosion.
We provide EN 10204 3.1 Material Test Certificates (MTC), heat codes for material traceability, PMI reports, third-party inspection certificates, and hydrostatic test reports.
For standard samples, the lead time is approximately 7 days. Mass production orders generally ship within 20 to 30 days after receipt of down payment and approval of specifications.
We accept standard corporate bank transfers (T/T), with a 30% deposit in advance and the remaining 70% balance payable upon presentation of the Bill of Lading (B/L) copy. We also accept Western Union and PayPal for smaller orders.
For international shipments, we package coiled tubing on heavy-duty wooden reels wrapped in protective plastic. Straight pipes are bundled in sea-worthy steel-capped crates to protect the tube ends and outer surfaces from mechanical damage during transit.
A complete selection of grades, sheets, and coils ready for commercial shipment.
Factory-certified product lines designed for modern industrial engineering requirements.
