Sihe Steel
Sihe Steel
Inconel 625 (UNS N06625) is a nickel-chromium-molybdenum alloy that is highly valued for its high strength, outstanding fabricability (including joining), and superb corrosion resistance. The addition of niobium reacts with molybdenum to stiffen the alloy’s matrix, providing high strength without requiring a strengthening heat treatment.
When drawn into capillary tubing (typically referring to outer diameters under 6.35mm with wall thickness constraints), the alloy maintains its structural soundness under severe conditions. In subsea environments, aerospace hydraulic channels, and high-pressure chemical dosing systems, capillary tubing is subjected to high mechanical loads and aggressive chemistries like sour gases ($H_2S$), chlorides, and high concentrations of mineral acids.
Nickel (Ni): 58.0% Min | Chromium (Cr): 20.0% – 23.0%
Molybdenum (Mo): 8.0% – 10.0% | Niobium + Tantalum (Nb+Ta): 3.15% – 4.15%
Density: 8.44 g/cm³ | Melting Point: 1290–1350°C
Standard austenitic stainless steels like 316L face localized pitting and crevice corrosion when exposed to seawater or high-chloride environments at elevated temperatures. In contrast, Alloy 625 has a Pitting Resistance Equivalent Number (PREN) exceeding 45, making it practically immune to chloride-induced stress corrosion cracking (SCC).
In capillary sizes, the tubing is often utilized as hydraulic control lines, subsea umbilical injection lines, and high-precision instrument conduits. A key factor is the high yield strength (>415 MPa) and tensile strength (>825 MPa) in the annealed state, which allow designers to reduce wall thickness while maintaining high internal pressure rating, optimizing flow rates and space utilization in tight design configurations.
Liaocheng Sihe Stainless Steel Material LTD represents the cutting edge of manufacturing high-performance nickel alloy and stainless steel coiled tubes in China. Our facility integrates the world’s leading online bright annealing technology. Bright annealing under protective atmospheres (such as pure hydrogen) prevents surface oxidation, resulting in a scale-free, high-gloss interior and exterior surface that is essential for ultra-clean applications in semiconductor gas delivery and critical instrumentation.
To guarantee 100% reliability in high-risk environments, every linear meter of our 625 stainless steel capillary tubing undergoes strict testing regimes before shipping:
Our manufacturing limits span from outer diameters of 0.125 inch (3.175 mm) up to 1 inch (25.4 mm), with wall thicknesses ranging up to 0.165 inch (3 mm). Lengths up to 10,000 meters (32,800 feet) allow for seamless subsea umbilicals with no orbital welds.
From subsea oil extractions in harsh waters to high-precision analytical equipment, Alloy 625 capillary tubes provide critical components for challenging environments.
As oil and gas exploration pushes further offshore, subsea oil and gas extractions require components that can withstand high hydrostatic pressures, chloride levels, and corrosive environments. Using Alloy 625 coiled tubes for chemical injection and hydraulic control lines reduces mechanical risk, preventing costly environmental issues or subsea well interventions.
In laboratory gas chromatography, pharmaceutical production, and semiconductor fabrication facilities, gas delivery lines must not contaminate the fluid or react with process reagents. Our bright annealed capillary tubes offer exceptionally smooth, clean inner surfaces, reducing chemical retention and ensuring high accuracy in critical analytical processes.
2205 duplex, 2507 super duplex, and 316L/317L high-performance stainless steel coils for hydraulic control and chemical injection.
High-precision thin-wall capillary tubing for chromatography, medical devices, aerospace sensors, and high-purity instrumentation.
Seamless and welded coils configured for boilers, condenser lines, and high-efficiency thermal exchangers operating in corrosive media.
We support various materials (e.g., 304, 316L, 2205, Inconel 625, Incoloy 825) and specifications (diameter 6.35mm to 19mm and smaller capillaries) for high-grade steel and nickel coils.
Custom precision bending, tight-radius spiral coiling, and high-density packaging tailored for subsea pod assemblies and space-restricted heat exchangers.
Laser cutting, mechanical cold-cut shearing, or precision abrasive cutting to achieve minimal burr formation, tight length tolerances, and high-straightness metrics.
In-house chemical pickling, mechanical polishing, and passivation services designed to enhance critical surface metrics and resistance to corrosion.
Pre-engineered flanged connections, orbital welding prep, and custom sleeve fitting commonly used in subsea control lines and automotive exhaust integrations.
We manage our production under strict adherence to ISO 9001 quality systems and critical industry credentials. All raw materials are tracked from smelt to finished products.
