Sihe Steel
Sihe Steel
Select from our standard industrial configurations engineered strictly to GB, ASTM, ASME, JIS, and EN requirements.
As a global leader in high-performance metallurgy, Liaocheng Sihe Stainless Steel Material Ltd has pioneered the manufacturing and supply of premium quality stainless steel coiled tubes, capillary tubes, and heat exchanger pipes. Based in China, we manage six highly advanced continuous production lines utilizing online bright annealing and precision drawing technologies.
Our commitment to material integrity and compliance drives our strict alignment with global standards, including GB, ASTM, ASME, JIS, and EN. We maintain full traceability of our chemical alloys, working with elite grades: 304/304L, 316L, 321, 317L, 309S, 310S, INCOLOY 800, Incoloy 825, Inconel 625, and Duplex 2205 / 2507. By providing ultra-long coiled tubing with zero orbital welds, we optimize hydraulic safety, reduce leakage vectors, and streamline offshore umbilical assemblies.
ASTM 316L is an extra-low-carbon variation of the molybdenum-bearing austenitic chromium-nickel alloy. The integration of 2% to 3% Molybdenum (Mo) significantly boosts the material's Pitting Resistance Equivalent Number (PREN) compared to standard 304 grades, rendering it highly resistant to localized pitting, crevice corrosion, and chloride-rich stress corrosion cracking (SCC).
By keeping carbon content below 0.03%, Liaocheng Sihe ensures that our ASTM 316L tubes prevent carbide precipitation at grain boundaries during high-temperature exposures or localized welding. This eliminates the risk of intergranular corrosion, maintaining structural strength and fatigue resistance in heavy-duty oil and gas extraction plants, subsea umbilicals, and process lines.
| Alloy Grade | C (%) | Mn (%) | Si (%) | P (%) | S (%) | Cr (%) | Ni (%) | Mo (%) | PREN |
|---|---|---|---|---|---|---|---|---|---|
| 316L (UNS S31603) | ≤ 0.030 | ≤ 2.00 | ≤ 0.75 | ≤ 0.045 | ≤ 0.030 | 16.0 - 18.0 | 10.0 - 14.0 | 2.00 - 3.00 | > 23.1 |
| 304L (UNS S30403) | ≤ 0.030 | ≤ 2.00 | ≤ 0.75 | ≤ 0.045 | ≤ 0.030 | 18.0 - 20.0 | 8.0 - 12.0 | - | > 18.0 |
| Duplex 2205 | ≤ 0.030 | ≤ 2.00 | ≤ 1.00 | ≤ 0.030 | ≤ 0.020 | 22.0 - 23.0 | 4.5 - 6.5 | 3.00 - 3.50 | > 35.0 |
Liaocheng Sihe is equipped to manufacture coiled tubing across a versatile specification matrix. Our precision cold-drawing lines produce continuous coiled tubing starting from an outer diameter (OD) of 0.125 inches (3.175 mm) up to 1 inch (25.4 mm). The wall thickness is engineered to match pressure ratings, reaching up to 0.165 inches (3.0 mm).
For subsea controls and chemical injection umbilicals, we deliver continuous single-length coils up to 32,800 feet (10,000 meters). The omission of joints minimizes potential mechanical failures and reduces assembly cost. Furthermore, we offer custom dimension profiles, meeting precise OD and ID tolerances as strict as ±0.05 mm, ensuring seamless integration with standard compression fittings.
Analyzing how macroscopic energy and industrial infrastructure evolutions shape the demand for advanced coiled tubing systems.
As onshore reserves deplete, offshore oil and gas developments are transitioning to deeper, higher-pressure zones. Umbilical cables running thousands of meters to subsea wellheads demand control lines that possess exceptional mechanical fatigue strength. Standard welded tubing increases susceptibility to micro-cracking and stress failures. Liaocheng Sihe's seamless coiled tubes alleviate these risks, providing reliable hydraulic pathways at extreme pressures.
The green energy transition has prompted the expansion of hydrogen fueling stations and CO2 capture facilities (CCUS). Gaseous hydrogen molecular structure is prone to diffusing through metals, causing hydrogen embrittlement in standard carbon steels. Bright-annealed, low-carbon ASTM 316L and Duplex 2205 coiled tubing systems offer a superior crystalline lattice that resists hydrogen diffusion and keeps gas delivery lines safe.
The microelectronics and semiconductor fabrication industries require ultra-pure gas and chemical delivery pipelines. The internal surface roughness (Ra) of the tubing must be exceptionally low to prevent particle entrapment. Our state-of-the-art bright annealing line ensures an internally clean, smooth surface profile (Ra ≤ 0.4 μm), eliminating the need for expensive mechanical polishing before installation.
Liaocheng Sihe's coiled tubes are critical components deployed across major engineering fields globally.
Continuous coil designs reduce tube-to-sheet joint counts by up to 90%, eliminating localized leakage risks in high-temperature systems.
Maintains consistent thermal conductivity and structural flexibility, facilitating tighter, more compact loop bending.
Withstands heavy exposure to acidic media (sulfuric, acetic, and phosphoric acids) without intergranular decay.
Food-grade safe metallurgy (non-toxic, non-reactive passivation layer) preventing material leaching and product contamination.
Strict compliance with hygienic processing equipment standards. Prevents biofilm development inside pipelines.
Handles high-pressure steam distribution and condensed fluid return pathways with minimal thermal scaling.
Engineered for aggressive feedstocks, handling volatile hydrocarbons safely over long distance transport loops.
Critical hydraulic lines, fuel delivery lines, and instrumentation control lines that require light-weight high-strength integrity.
Liaocheng Sihe is not merely a material manufacturer; we provide fully integrated downstream processing services to customize products to exact structural blueprints.
Our workshop facilitates customized bending, mechanical forming, and spiral profile coiling. We handle diverse grades including 304, 316L, and Duplex 2205 in standard sizing (typically 6.35mm to 19.05mm OD) to deliver structural coils ready for heat exchanger chambers.
We utilize specialized internal mandrel drawing, custom tooling, and automated cold-drawing rigs. This ensures consistent wall uniformity, which is vital for hydraulic actuators and safety-critical subsea control lines.
With high-speed automated laser cutting and precision rotational straightening machines, we achieve distortion-free, straight tubing lengths with highly precise perpendicular end-cuts.
Our facility includes continuous acid pickling, ultrasonic solvent cleaning, and chemical passivation. These treatments optimize the passive chromium oxide layer, giving our products a high resistance to salt-spray and acidic corrosion.
Used widely in automotive exhaust manifolds and chemical flow networks, our end-forming lines produce custom flanged, swaged, or flared ends to support secure, leak-free compression couplings.
Explore our primary divisions specializing in structural and instrumentation tubing.
Duplex 2205 containing austenitic and ferritic structures, offering double the strength of 316L with supreme chloride pitting resistance.
1/2 inch stainless steel coiled tubing refers to precision dimension coils for hydraulic controls and structural piping.
Highly resistant to high temperature oxidation, designed specifically for heat-treatment furnaces and exhaust systems.
To ensure failure-free operations in extreme offshore settings, we deploy an exhaustive quality testing protocol. Every batch of our ASTM 316L coiled tubing undergoes critical mechanical, hydraulic, and non-destructive evaluations before dispatch:
Our flaring tests verify material ductility and expansion capacity without cracking. Bend tests confirm the tube can safely transition into small radius loops under tension.
We execute hardness testing along the entire coil length to guarantee a uniform grain structure, which is crucial for preventing localized stress hotspots.
Each coil is pressurized with dry air or clean water at specified PSI ratings to verify leak-proof integrity, fulfilling subsea requirements.
The global demand for high corrosion-resistant alloys continues to evolve. Liaocheng Sihe is investing in next-generation processing lines to increase the production of nickel superalloys (Incoloy 825, Inconel 625) and Super Duplex 2507 coiled tubes. These alloys possess high mechanical strength and are designed for extreme subsea environments with high concentrations of H2S and CO2.
Our research and development centers on reducing the internal surface roughness of coiled tubes to support semiconductor manufacturing. Through hydrogen-purged bright annealing improvements, we are striving to reach an Ra of ≤ 0.2 μm without post-drawing mechanical processes. Additionally, we are exploring green manufacturing practices to minimize emissions during heat treatment.
Addressing technical questions and procurement details regarding ASTM 316L stainless steel coiled tubing.
Expanding engineering capabilities with high-alloy configurations, welded pipes, and customized dimensions.
