Sihe Steel
Sihe Steel
Explore our certified range of high-performance alloy tubing manufactured to exceed international quality metrics.
A deep engineering dive into the chemical metallurgy and mechanical integrity of critical nickel-iron-chromium alloys.
The manufacturing and structural criteria governing ASTM A269 825 stainless steel coil tubes are designed to solve one of modern engineering's greatest challenges: preserving mechanical integrity and material lifetime under severe acidic and chloride-rich environments. The alloy itself, Incoloy 825 (UNS N08825), is a nickel-iron-chromium-molybdenum-copper compound engineered specifically to combat localized pitting, general stress-corrosion cracking (SCC), and intergranular carbide precipitation.
Unlike standard 300-series austenitic steels such as 304 or 316L, Alloy 825 features a high nickel content (38% to 46%) which provides complete resistance to chloride-induced stress corrosion. When structured into continuous coiled tubing under the strict dimensional tolerances of ASTM A269, it achieves exceptional pressure-containment capability and mechanical flexibility. This standard specifies precise parameters for outer diameter (OD) control, wall thickness (WT) deviation limits, tensile properties, and mandatory non-destructive examination (NDE) methods.
By eliminating multiple orbital field welds over ultra-long configurations (up to 32,800 feet), coiled tubing reduces leakage risks and simplifies the complex architecture of subsea downhole control systems and heat exchangers.
| Element | Composition Limits (Alloy 825) |
|---|---|
| Nickel (Ni) | 38.0% – 46.0% |
| Chromium (Cr) | 19.5% – 23.5% |
| Iron (Fe) | Balance (min 22.0%) |
| Molybdenum (Mo) | 2.5% – 3.5% |
| Copper (Cu) | 1.5% – 3.0% |
| Titanium (Ti) | 0.6% – 1.2% (Stabilizing agent) |
Years of Production History
Active Production Lines
Maximum Continuous Length
Testing & Quality Compliance
Liaocheng Sihe Stainless Steel Material LTD integrates smart technology to manufacture ultra-long high-pressure coiled tubing.
At our advanced manufacturing facility, operated by Liaocheng Sihe Stainless Steel Material LTD, we utilize state-of-the-art metallurgical technologies across our 6 specialized production lines. Having refined our processes over a 10-year manufacturing history, we are equipped to support demanding structural programs globally. We specialize in producing seamless coiled tubing reaching lengths up to 32,800 feet (10,000 meters) without orbital joint welds.
Our infrastructure introduces world-class bright annealing technology, allowing inline atmosphere control and high-efficiency material softening. Through automated cooling profiles, this process ensures excellent structural homogeneity and prevents chromium carbide precipitation at grain boundaries. Our comprehensive testing protocol guarantees performance under pressure, comprising 100% mechanical compression tests, flaring, bending, 100% hardness tests, tensile testing, and high-precision air tightness evaluation.
We manufacture strictly to GB, ASTM, ASME, JIS, and EN standards. Our extensive steel grades portfolio includes Austenitic (304/304L, 316L, 321, 317L, 309S, 310S, INCOLOY 800), Duplex (2205), Super Duplex (2507), Incoloy 825, and Inconel 625.
Our coiled tubes are available in outer diameters ranging from 0.125 inches (3.175 mm) up to 1 inch (25.4 mm), with wall thicknesses up to 0.165 inches (3.0 mm) depending on technical application requirements.
With an export footprint spanning over 30 countries—including the United States, Germany, Spain, South America, Southeast Asia, the Middle East, and Eastern Europe—we provide reliable ocean and air freight logistics solutions.
Providing corrosion-resistant alloy infrastructure to support mission-critical global industrial applications.
For operations extending into deep and ultra-deepwaters, high-pressure subsea control umbilicals demand reliable safety. Our Incoloy 825 coiled tubes resist sour gas mixtures containing hydrogen sulfide (H2S), carbon dioxide (CO2), and high chloride concentrations, preventing pitting, stress corrosion cracking, and structural failure.
Processing aggressive acids like sulfuric, phosphoric, and organic media requires robust alloy infrastructure. The inclusion of copper and molybdenum in Alloy 825 provides superior resistance to reducing chemicals, optimizing runtime and minimizing unscheduled maintenance across chemical plants.
Geothermal energy production and high-temperature solar concentration systems expose heat exchangers and process piping to thermal stress and mineral-rich brine. Our ASTM A269 compliant coiled tubing maintains its structural stability and corrosion resistance at elevated temperatures.
Predicting metallurgical and quality challenges in future extreme-environment applications.
As deepwater exploration reaches depths exceeding 10,000 feet, downhole pressures can surpass 20,000 PSI, accompanied by temperatures above 200°C. Standard alloys often reach their physical limits under these conditions. Our metallurgical research program focuses on three main development goals to optimize performance in these demanding applications:
Deploying electro-polishing (EP) on long coiled inner diameters to achieve roughness levels below Ra 0.25μm, minimizing deposit formation in critical environments.
Evaluating custom nickel-iron-chromium chemistries designed for ultra-high temperature operations up to 650°C, maintaining microstructural stability.
Integrating real-time digital eddy-current testing with continuous laser dimensional profiling during the high-speed coiling phase to ensure zero-defect tube runs.
A comprehensive roadmap for procurement managers evaluating long-term supply agreements.
For international supply agreements, compliance documentation remains paramount. Every production run must be traceable to the source ladle. We provide certified Material Test Reports (MTR) conforming to EN 10204 3.1, incorporating chemical composition, actual yield/tensile strength, elongation, hardness metrics, and complete hydrostatic testing results.
Large-scale projects require reliable delivery schedules. Standard manufacturing schedules require 20 to 30 days post-deposit and specification finalization, while custom-ordered sample tubes can be prepared within 7 days. We coordinate production schedules to match installation windows, avoiding costly delays.
Continuous coiled tubing requires protective transport wrapping. We utilize heavy-duty metal or reinforced wooden drums lined with moisture-proof materials to prevent damage during sea transport. Custom protective systems are applied to eliminate seawater contact and physical damage during handling.
Our quality management system is certified by international inspection authorities, ensuring full process traceability.
Quality Management
ISO 9001:2015
API Monogram License
Specification Q1 & 5LC
PED Certification
Directive 2014/68/EU
Marine Approvals
DNV, ABS, & LRS
Environmental Control
ISO 14001:2015
Occupational Health
ISO 45001:2018
CNAS Accreditation
Laboratory Testing ISO 17025
TÜV AD 2000-W0
Pressure Vessel Materials
Industrial License
National Safety Standard
CE Conformity
European Union Standards
BV Certification
Production Plant Approval
SGS Inspection
Third-Party Quality Report
Detailed engineering and procurement insights to guide your purchasing decisions.
Providing precision post-processing options to meet project-specific dimensional and structural requirements.
We provide structural pre-forming, spiral coiling, and compact winding of stainless steel tubing to match heat exchanger configurations, downhole assemblies, and chemical reactor systems.
Utilizing high-precision laser and mechanical cutting lines to provide precise lengths. We ensure straightness parameters and square-cut ends to simplify orbital welding operations.
We perform controlled acid pickling, electro-polishing, and chemical passivation to eliminate surface impurities and carbon contamination, maximizing corrosion resistance.
Explore our wider range of stainless steel products, sheets, and specialty tubing configurations.
