Sihe Steel
Sihe Steel
Explore our industrial-grade, precision-engineered seamless and welded stainless steel pipe solutions. Retaining full direct sourcing channels.
Years Production Experience
High-Precision Mill Lines
Global Export Destination Countries
Hydrostatic & Eddy Testing
In modern global heavy industries, structural integrity, high-pressure capabilities, and anti-corrosive properties are critical criteria. Seamless stainless steel pipes of grades 304 and 304L (UNS S30400 & UNS S30403) serve as the primary conduits for transporting volatile fluids, high-temperature gases, and high-purity chemical components.
By omitting longitudinal welds, seamless manufacturing techniques ensure uniform microstructures and prevent localized stress failures. Consequently, global engineers prioritize ASTM A312, ASTM A269, and ASME SA213 specifications for chemical refineries, clean semiconductor cleanrooms, offshore umbilicals, and energy heat exchangers.
As a leading expert in the steel manufacturing industry, Liaocheng Sihe Stainless Steel Material LTD manufactures high-quality sheets and pipes according to strict global production standards: GB, ASTM, ASME, JIS, and EN. We specialize in custom-engineered coiled tubing, bright annealed capillary lines, and high-tolerance structural pipes.
Understanding the carbon composition limit is essential for structural weldability and preventing intergranular corrosion in processed pipeline environments.
The fundamental difference between Grade 304 and Grade 304L lies in their carbon concentrations. Grade 304 permits a maximum carbon content of 0.08%, while 304L restricts carbon to a maximum of 0.03%. This lower carbon range prevents sensitization—the precipitation of chromium carbides at grain boundaries during welding or high-temperature exposures.
| Steel Grade (UNS) | Carbon (C) Max % | Chromium (Cr) % | Nickel (Ni) % | Tensile Strength (MPa) Min | Yield Strength (MPa) Min | Elongation (%) Min |
|---|---|---|---|---|---|---|
| 304 (UNS S30400) | 0.08 | 18.0 - 20.0 | 8.0 - 10.5 | 515 | 205 | 40 |
| 304L (UNS S30403) | 0.03 | 18.0 - 20.0 | 8.0 - 12.0 | 485 | 170 | 40 |
| 316L (UNS S31603) | 0.03 | 16.0 - 18.0 | 10.0 - 14.0 | 485 | 170 | 40 |
| Duplex 2205 (UNS S31803) | 0.03 | 22.0 - 23.0 | 4.5 - 6.5 | 655 | 450 | 25 |
The ultra-low carbon level in 304L minimizes the risk of intergranular corrosion, making post-weld heat annealing unnecessary for most piping geometries.
Austenitic stainless steels retain their ductility and impact strength at extremely low temperatures, preventing brittle structural failures.
These grades possess excellent work-hardening characteristics, enabling precision cold-drawing and high-ratio surface polishing.
Operating with a decade-long production history, Liaocheng Sihe Stainless Steel Material LTD manufactures steel tubing using three specialized coil production lines and six structural processing lines. We implement world-class online bright annealing (BA) technologies to heat-treat products in a controlled reducing atmosphere. This process eliminates internal mechanical stresses while maintaining a smooth, mirror-like finish.
Our seamless coiled tubing is available in outer diameters ranging from 0.125 inches (3.175 mm) to 1 inch (25.4 mm), with wall thicknesses up to 0.165 inches (3 mm). We also manufacture continuous, orbital-weld-free lines in lengths up to 32,800 feet (10,000 meters). These continuous lines are essential for deepwater umbilicals, reducing leak risks at connection points.
To ensure complete quality compliance, we conduct comprehensive testing, including hydrostatic testing, air tightness checks, tensile strength testing, flaring/flattening tests, and 100% hardness verifications.
Seamless piping is used in critical applications where safety and structural integrity are paramount. We match specific steel grades with environmental requirements.
Requires high heat transfer efficiency and resistance to localized stress corrosion cracking. Utilizes high-precision 304/304L bright annealed tubes for optimized flow dynamics.
Seamless coiled tubing prevents refrigerant leaks under cyclic thermal stresses, providing reliable containment in HVAC environments.
Designed for chemical processing pipelines. Features high resistance to organic solvents, acidic vapors, and volatile compounds.
Features ultra-smooth mechanical inner polishing to prevent bacteria buildup, meeting international sanitary and hygiene regulations.
Utilizes ultra-high purity (UHP) capillary tubes for chromatography and fluid instrumentation, preventing trace metal contamination.
Engineered for high-temperature superheater steam lines and high-pressure feedwater cycles, maintaining mechanical strength and scale resistance.
Resists sulfide stress cracking and corrosion in refining processes, providing long-term reliability in high-pressure installations.
High-strength capillary tubes and flanged exhaust lines designed for high-vibration aerospace hydraulics and automotive common-rail fuel systems.
We provide in-house post-drawing manufacturing options to meet demanding structural specifications.
Supports multiple austenitic and duplex grades (304, 316L, 2205). Standard outer diameters range from 6.35 mm to 19 mm, tailored to custom layout requirements.
Specialized processing for heat exchangers, including helical coils, tight-radius U-bending, complex geometries, and custom spiral wrapping.
Equipped with laser, disk-saw, and flame cutting technologies. Restricts length tolerances to ±0.5 mm while maintaining square, burr-free ends.
Bright annealing (BA), mechanical grinding, chemical pickling, and electropolishing (EP) to meet strict roughness requirements (Ra < 0.25 µm).
High-precision flanged connections designed for automotive exhaust systems, corrosive chemical lines, and laboratory equipment.
Custom sizing options for non-standard wall thicknesses and tight tolerances, designed to meet specific engineering criteria.
Liaocheng Sihe is ISO-registered and qualified to provide test reports (EN 10204 3.1) and certificates of conformity for safety-critical systems.
Important factors to consider when ordering high-volume stainless steel pipe shipments internationally.
Sample processing typically requires 7 business days, while volume production runs take between 20 to 30 days. Timelines start upon deposit receipt and technical drawing sign-off.
Standard payment terms are structured as a 30% deposit in advance, with the remaining 70% balance due upon presentation of the Bill of Lading (B/L) copy. We accept wire transfers (T/T), L/C, Western Union, and PayPal.
Tubing is packed in heavy-duty wooden crates or steel-framed boxes to prevent deformation during sea freight. Specialized ocean transport is used for long length continuous coils.
Our core manufacturing range covers five main stainless steel categories, designed to meet specific chemical, structural, and pressure requirements.
Duplex 2205 contains mixed austenitic and ferritic microstructures for high strength and corrosion resistance.
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Standard 1/2 inch coiled stainless tubing designed for instrumentation and downhole oilfield lines.
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High-temperature grade 310 stainless steel tubing designed to resist scaling and oxidation.
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Precision drawn tubing with high surface finish and tight dimensional tolerances.
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High-pressure hydraulic control line designed for offshore installations and aerospace systems.
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Corrosion-resistant tubing designed for deepsea subsea distribution manifolds and injection lines.
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Micro-bore tubing designed for analytical instruments, chromatography systems, and pressure gauges.
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Super Duplex grade designed for marine installations and highly acidic environments.
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High-performance nickel-chromium alloy designed for extreme chemical exposures and high temperatures.
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Seamless thermal exchange pipes designed for power generation systems and industrial boilers.
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Featuring a bright finish on both inner and outer surfaces, designed for clean fluid transfer.
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Designed for biological processing plants, food production lines, and clean water systems.
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High-precision, thin-walled tubing designed for automotive fuel rails and control systems.
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Nickel-iron-chromium alloy designed for high resistance to stress corrosion cracking in sour environments.
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Extruded seamless nickel alloy tubing designed for high-stress offshore applications.
View More ProductGet professional advice on material selection, pricing factors, testing standards, and compliance certifications.
Review the second half of our high-integrity metallurgical line, including special superalloys and custom sheet profiles.
