Sihe Steel
Sihe Steel
Engineered to withstand harsh corrosive environments. Explore our range of high-performance alloy tubing manufactured under rigorous ASME and ASTM standards.
A Technical Deep Dive into Intergranular Corrosion Resistance and Metallurgical Optimization
In high-pressure and corrosive fluid transport, austenitic stainless steels like TP316/316L are subjected to severe stress. When these alloys are exposed to temperatures ranging from 425°C to 815°C (800°F to 1500°F) during welding, processing, or services, chromium carbides precipitate along the grain boundaries. This precipitation causes chromium depletion in the areas immediately adjacent to the grain boundaries, making the tube susceptible to Intergranular Corrosion (IGC).
ASME A262 outlines the standardized testing methodologies to detect susceptibility to IGA. As a premier manufacturer, Liaocheng Sihe strictly administers these tests, ensuring that every batch of TP316 coiled tubes exhibits optimal grain structures and maintains resistance under highly corrosive operating conditions.
Liaocheng Sihe guarantees 100% compliance with Practice A & E on all TP316/316L coil orders destined for deepwater and chemical applications.
Comparison of metallurgical evaluations and composition requirements for TP316 and TP316L grades.
| Grade Spec | Carbon (C) Max % | Molybdenum (Mo) % | ASME A262 Practice Compatibility | Corrosion Testing Duration | Primary Application Fit |
|---|---|---|---|---|---|
| ASME TP316 | 0.080 | 2.00 - 3.00 | Practice A, B, C | Varies (up to 120 hours) | General industrial, instrumentation, heat exchangers |
| ASME TP316L | 0.030 | 2.00 - 3.00 | Practice A, E (Strauss Test) | 15 hours boiling + bend test | Deepwater umbilicals, orbital welding cleanrooms, sour service |
| Duplex 2205 | 0.030 | 3.00 - 3.50 | ASTM A923 Methods | Charpy impact / chemical etch | High pressure subsea manifolds, heavy chemical transport |
| Inconel 625 | 0.100 | 8.00 - 10.00 | ASTM G48 (Pitting/Crevice) | 72 hours minimum | Extreme offshore geothermal, ultra-deep oil exploration |
How Liaocheng Sihe integrates advanced metallurgical engineering with cold-drawing and bright annealing technologies.
Our raw mother tubes are sourced from leading smelters. They undergo multi-stage cold-drawing and cold-rolling to ensure uniform outer diameters (OD) ranging from 0.125" to 1" and wall thickness (WT) up to 0.165" with tight tolerances (±0.05mm).
Equipped with world-class online bright annealing technology, we heat the tubes to 1040°C - 1150°C in a pure hydrogen atmosphere. Rapid gas quenching prevents oxide scaling and dissolves chromium carbides, ensuring high ductility and corrosion resistance.
We execute 100% non-destructive testing (NDT), including online Eddy Current, pneumatic testing, hydrostatic testing at pressures up to 10,000 PSI, flaring and flattening tests, and hardness checks to guarantee zero leakage throughout long spools.
A decade of leadership in the international stainless steel coiled tubing market.
Production Lines
Years Manufacturing Experience
Max Continuous Length (32,800 ft)
Countries Exported Globally
Our factory in China specializes in long-length seamless and welded coils. Over 80% of our products are exported to demanding markets in the US, Germany, Spain, South America, Southeast Asia, the Middle East, and Eastern Europe.
Whether you require standard 304/304L, 316/316L, or high-performance Duplex 2205, Super Duplex 2507, Inconel 625, or Incoloy 825, our engineering team manufactures custom dimensions matching ASME SA213, ASTM A269, ASTM A789, and EN 10216-5 standards.
Where high reliability and strict ASME A262 compliance are mandatory.
Continuous coiled tubing eliminates joint leaks in shell-and-tube heat exchangers, preventing cross-contamination in harsh chemical process streams.
Handling acidic, high-chloride, and chemical mixtures. Strict ASME A262 compliance prevents corrosion and localized pitting under intense operational stress.
Ultra-pure transport lines require smooth, high-precision inside diameters (ID) that facilitate clean-in-place (CIP) operations without particulate collection.
How our localized production model lowers total cost of ownership for international buyers.
Liaocheng Sihe is situated within China's steel manufacturing cluster. This provides us with direct, priority access to high-purity, vacuum-induction melted (VIM) and electroslag refined (ESR) billets from top-tier domestic mills like Baosteel and TISCO. By sourcing prime material, we maintain full control over chemistry parameters, including nickel, molybdenum, and carbon levels.
Our integrated manufacturing line supports processing, bright annealing, cold drawing, and packaging under one roof, reducing lead times to 20-30 days for bulk production. This vertical integration buffers our clients from price volatility and local logistical bottlenecks, allowing us to supply ASTM A269 and ASME A262-tested coiled tubing with consistent quality at competitive prices.
Value-added processing to meet custom technical requirements.
Custom precision spiral winding and multi-axis bending services for compact heat exchangers, subsea valves, and marine cooling systems.
Using advanced laser systems and mechanical straightening, we deliver pre-cut lengths with burr-free ends, ready for immediate installation.
Offering options from standard bright annealed (BA) to electropolished (EP) finishes, meeting the surface roughness requirements of UHP gas systems.
We process standard flares and flanged connections for quick mechanical assembly in high-pressure oil and chemical manifolds.
Liaocheng Sihe operates under international quality management systems, assuring compliance for hazardous applications.
We also provide additional testing reports upon request, including ASTM G48 pitting test results, ASME A262 Practice E Strauss reports, PMI (Positive Material Identification) verification, and helium leak testing certificates.
Technical guidance and commercial support for global procurement managers.
Our pricing fluctuates based on raw material costs (specifically nickel and molybdenum alloys) and shipping rates. Once your company submits an inquiry with specifications, dimensions, and order volume, we will prepare an updated price list. We offer FOB, CIF, or DDP delivery terms depending on your local logistics setup.
For custom production runs of special alloys (e.g., Inconel 625 or Duplex 2205) or non-standard wall thicknesses, we require a minimum order quantity. This ensures an efficient machine setup and rolling sequence. For common grades like TP316L, we can support smaller trial orders. Please contact our sales team to discuss your project requirements.
Yes. Every shipment is accompanied by a Mill Test Certificate (MTC) conforming to EN 10204 3.1. This documentation includes chemical analysis (carbon, chromium, nickel, molybdenum, manganese), mechanical testing (tensile strength, yield strength, elongation, hardness), hydrostatic pressure test records, and ASME A262 Practice A or E corrosion test certificates.
Sample orders are typically ready for dispatch within 7 days. For mass production runs, the standard lead time is 20-30 days after receiving the deposit and confirming drawing specifications. Lead times commence upon: (1) receipt of your initial deposit, and (2) final technical approval of the product design sheet. We work to align production timelines with your project schedule.
We accept wire transfers (T/T), L/C at sight, Western Union, and PayPal. Our standard commercial terms are a 30% deposit in advance, with the 70% balance paid against a copy of the Bill of Lading (B/L) and quality release reports.
Long continuous coil tubes are spooled on wooden or metal reels, wrapped in protective plastic sheeting, and packed into solid, seaworthy wooden crates. This packaging protects the tubing from mechanical damage, bending, and saltwater exposure during sea transit.
We manufacture a wide range of corrosion-resistant solutions.
Duplex 2205 and 2507 flexible seamless coils are designed for high mechanical strength and subsea corrosion resistance.
1/2" OD stainless steel coiled tubing in continuous lengths, engineered for steam trace lines and subsea control umbilicals.
Designed for high-temperature service up to 1100°C, our 310 grade coil tubes are used in boilers and furnace environments.
Direct sourcing from our Liaocheng manufacturing facility. Custom tolerances, alloy grades, and packaging configurations available.
