Sihe Steel
Sihe Steel
High-precision seamless coiled tubes engineered for hazardous heat exchanger and processing applications.
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Competitive bulk quotes for welded instrumentation and condenser coils with premium bright annealing finish.
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Premium UNS N08904 alloys designed for superior sulfuric and phosphoric acid resistance in harsh environments.
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Extreme temperature resistant welded pipes constructed specifically for industrial exhaust and furnace duct systems.
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Highly customizable hydraulic control tubing available in long continuous coils without orbital welds.
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Specialized downhole control lines and chemical injection tubing with maximum structural reliability.
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High-temperature oxidation resistant pipes constructed for thermal recovery and power generation units.
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Micro-bore seamless tubes with polished internal surfaces for chromatography and precision measurement instruments.
View Details →In modern multi-layered industrial processes, raw material corrosion stands as one of the primary drivers of unexpected downtime, safety hazards, and massive capital expenditures. Alloy 904L (UNS N08904) represents a pinnacle of austenitic technology, offering a highly robust solution in environments where standard grades like 316L fail rapidly. Featuring a rich chemical blend of chromium, nickel, and molybdenum, paired with structured copper additions, 904L coil tubing provides exceptional resistance to strong reducing acids—particularly sulfuric acid.
Grade 904L is a fully austenitic low-carbon stainless steel. The addition of copper (typically 1-2%) yields unique chemical attributes, rendering the metal highly resistant to aggressive concentration curves of sulfuric, phosphoric, and acetic acids. Unlike standard austenitic alloys that undergo pitting and crevice corrosion in warm chloride environments, 904L exhibits a Pitting Resistance Equivalent Number (PREN) exceeding 34. This makes it a cost-effective bridging alloy between standard molybdenum-bearing steels (like 316L) and highly expensive nickel-base superalloys.
| Alloy Grade | UNS Number | Chromium (Cr) % | Nickel (Ni) % | Molybdenum (Mo) % | Copper (Cu) % | PREN Value |
|---|---|---|---|---|---|---|
| 316L | S31603 | 16.0 - 18.0 | 10.0 - 14.0 | 2.0 - 3.0 | - | ~23-25 |
| Duplex 2205 | S32205 | 22.0 - 23.0 | 4.5 - 6.5 | 3.0 - 3.5 | - | ~35-38 |
| 904L | N08904 | 19.0 - 23.0 | 23.0 - 28.0 | 4.5 - 5.0 | 1.0 - 2.0 | > 34 |
| Incoloy 825 | N08825 | 19.5 - 23.5 | 38.0 - 46.0 | 2.5 - 3.5 | 1.5 - 3.0 | ~31-33 |
Liaocheng Sihe Stainless Steel Material Ltd is a leading expert in the manufacturing and distribution of premium stainless steel coiled tubing, seamless capillary tubes, and high-performance polished pipes. Founded in China with over ten years of specialized manufacturing history, we operate six highly sophisticated production lines and three separate coil drawing lines designed to fulfill complex international specifications.
Equipped with state-of-the-art online bright annealing technologies to ensure maximum surface cleanliness, optimal ductility, and structural homogeneity.
Our QA protocols include 100% pneumatic testing, mechanical flaring, hydrostatic simulation, tensile limit testing, and precise micro-hardness mapping.
Exporting over 80% of our production capacity to over 30 countries across the US, Germany, Spain, South America, the Middle East, and Southeast Asia.
Our manufacturing portfolio follows strict international standards, including GB, ASTM, ASME, JIS, and EN specifications. The production program covers an extensive scope of steel grades including 304/304L, 316L, 321, 317L, 309S, 310S, INCOLOY 800, Austenitic 316L, Duplex 2205, Super Duplex 2507, Incoloy 825, and Inconel 625. Our coil tubing is available in custom dimensions from outer diameters of 0.125 inch (3.175 mm) up to 1 inch (25.4 mm), with wall thicknesses reaching 0.165 inch (3.0 mm) and single spool lengths up to 32,800 feet (10,000 meters) for umbilical assembly applications.
Stainless steel coiled tubing acts as a vital circulatory system in challenging industrial setups. By reducing connection points (joints and fittings), coiled tubing increases the physical integrity of fluid lines, eliminating potential leak paths and drastically shortening installation times.
Used in high-temperature condensation systems to prevent thermal cycling stresses and chloride-induced cracking.
Designed to handle high pressure eco-friendly refrigerants with zero leakage tolerances in heat pumps.
Excellent durability when conveying hot phosphoric, sulfuric, and organic acid combinations in chemical reactors.
Provides clean inner-surface finishes that prevent organic buildup and survive harsh CIP sanitization chemicals.
Strict adherence to sanitary tolerances prevents batch cross-contamination in fluid handling blocks.
Suitable for steam tracing, cooling water lines, and sensor instrumentation in utility boiler complexes.
Handles high-salinity downhole injection fluids and harsh sour gas environments without cracking.
Ideal for hydraulic fuel lines and engine instrumentation where lightweight and safety are paramount.
To match dynamic architectural and operational layouts, Liaocheng Sihe offers localized customization, converting raw coil tubes into ready-to-install hydraulic assemblies or component structures.
We support customized material matching (e.g., 304, 316L, 2205, 904L) with dynamic diameters from 6.35mm to 19mm. Custom wall thicknesses and coil geometries are calibrated to client specifications.
We process custom helical patterns, serpentine loops, and compact heat exchanger shapes. Advanced CNC bending eliminates micro-cracks at tight bend radii.
Our facility handles high-precision laser and mechanical cutting to deliver flat, burr-free ends. High-speed straightening lines restore standard roundness to coiled ends.
Includes electro-polishing (EP) and mechanical polishing processes. This reduces internal surface roughness (Ra) values, minimizing particulate trapping in sterile flow paths.
Tailored flanging processing allows seamless integration with heavy industrial connections. Crucial for secure installation in high-vibration automotive exhausts, chemical pipelines, and marine instrumentation.
Our production system is certified by major global auditing registers to ensure compatibility with European and North American pressure equipment codes.
As global energy sectors shift toward ultra-deepwater extraction and advanced carbon capture processes, materials face unprecedented stress profiles. Corrosive gas components (such as hydrogen sulfide and high-pressure carbon dioxide) require fluid control lines with superior chemical resistance. The technical evolution of 904L coiled tubing centers on three main development goals:
Eliminating weak points in fluid flow paths is critical for subsea applications. In deepwater control systems (umbilicals), intermediate welds pose risks of corrosion and mechanical failure under high-pressure cycles. Our manufacturing roadmap focuses on continuous cold drawing processes, extending single spool lengths beyond 10,000 meters while maintaining wall thickness uniformity within ±0.02 mm.
In hydrogen energy infrastructure and downhole oil tools, hydrogen atoms can diffuse into the metal lattice, causing embrittlement and catastrophic cracking. Our development initiatives concentrate on modifying nitrogen additions and managing trace elements to stabilize the austenite phase, minimizing hydrogen diffusion pathways.
Replacing traditional acid pickling processes with high-purity hydrogen bright annealing reduces chemical waste. The online atmospheric control system maintains a mirror-like interior surface, which improves flow dynamics and prevents scale accumulation in marine heat exchangers.
Procuring high-alloy materials like UNS N08904 (904L) requires a clear understanding of the variable factors that influence production costs. Because 904L contains high percentages of nickel (23-28%) and molybdenum (4-5%), its base price is closely linked to global alloy metal exchanges (such as the LME). Below is a breakdown of the primary price-setting mechanisms:
Fluctuations in global nickel, molybdenum, and copper prices directly impact base material costs. Spot price quotes are adjusted dynamically according to monthly metal surcharges.
Precision capillary sizes (e.g., OD < 3mm) require multiple cold-drawing and intermediate annealing steps, which increases processing costs compared to standard 1/2-inch tubing sizes.
Demands for third-party inspections (e.g., DNV, Lloyds, SGS) or advanced testing protocols (such as ultrasonic profiling or mechanical fatigue testing) are factored into final pricing.
For current, project-specific price sheets, please contact our sales department. We provide custom, volume-based pricing models that accommodate long-term supply agreements and distribution programs.
Grade 904L provides significantly better resistance to pitting and stress corrosion cracking in hot chloride solutions than 316L. The inclusion of copper and higher nickel levels in 904L helps resist hot sulfuric and phosphoric acids where 316L can experience rapid corrosion. This extended service life reduces maintenance intervals and helps prevent system contamination.
For custom configurations and standard mass production runs, the typical lead time is 20 to 30 days after receipt of the deposit. For small sample volumes or stock items, processing and dispatch can be completed within 7 business days.
Yes, we provide full quality documentation with all shipments, including EN 10204 3.1 Material Test Certificates, chemical composition analyses, physical test reports, and non-destructive eddy current testing records.
We typically accept a 30% advance deposit via T/T, with the remaining 70% balance due against the copy of the Bill of Lading (B/L). We also accept secure L/C terms, Western Union, and PayPal for sample orders.
For standard sizes, the MOQ starts at 500kg per size. For custom custom alloy configurations or non-standard profiles, the MOQ is determined based on the raw material casting requirements. Please contact our technical sales team to discuss your project needs.
Precision micro-bore tubes designed for high-pressure chromatographic applications.
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Polished round tubing engineered for hygienic pharmaceutical and food processing plants.
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Titanium-stabilized alloy plates offering high mechanical stability at elevated temperatures.
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Ferritic stainless steel sheets offering good corrosion resistance and formability for home appliances.
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Nickel-chromium-molybdenum alloy capillary tubes engineered for severe corrosive applications.
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Structural-grade corrosion resistant sheets suitable for marine structures and storage vessels.
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Cost-efficient sheets optimized for automotive exhaust systems and thermal barriers.
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High-strength duplex alloy capillary lines for extreme offshore environments.
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