Sihe Steel
Sihe Steel
Discover our premium range of stainless steel coils, tubing, capillary pipes, and plates manufactured to international standard regulations.
The optimal low-carbon alloy selected for severe fabrication conditions and critical corrosive service applications.
304L stainless steel (UNS S30403) is the ultra-low carbon variant of the standard 304 austenitic alloy. By restricting the carbon content to a maximum of 0.030% (compared to 0.08% max in grade 304), this grade successfully eliminates the risk of intergranular corrosion caused by carbide precipitation during high-temperature exposure, most notably during welding processes. In modern manufacturing, this characteristic is essential for structural applications that do not undergo post-weld annealing.
| Element | Grade 304L (UNS S30403) (%) | Grade 304 (UNS S30400) (%) | Technical Influence |
|---|---|---|---|
| Carbon (C) | 0.030 Max | 0.080 Max | Suppresses Chromium Carbide formation at grain boundaries during welding. |
| Chromium (Cr) | 18.00 - 20.00 | 18.00 - 20.00 | Provides the protective passive surface film essential for corrosion resistance. |
| Nickel (Ni) | 8.00 - 12.00 | 8.00 - 10.50 | Stabilizes the ductile austenitic matrix at room and cryogenic temperatures. |
| Manganese (Mn) | 2.00 Max | 2.00 Max | Aids in hot workability and acts as an effective deoxidizer. |
| Nitrogen (N) | 0.10 Max | 0.10 Max | Compensates for the yield strength drop associated with lower carbon levels. |
Despite its reduced carbon composition, the addition of nitrogen ensures that 304L maintains substantial load-bearing capacities. The minimum tensile strength is rated at 485 MPa (70 ksi), and the minimum yield strength at 170 MPa (25 ksi), accompanied by an elongation rate exceeding 40% in standard tests. These properties guarantee high ductility, allowing the material to undergo rigorous stretch-forming, deep-drawing, and roll-forming procedures without micro-cracking.
The shifting landscape of heavy industries highlights the critical position of the 304L alloy in infrastructure, energy, and localized supply routes.
Decarbonization projects and advanced green energy networks depend on reliable materials. From liquefied natural gas (LNG) tankers to deep-sea umbilical cables, 304L's cryogenic properties remain a foundational technical requirement.
Modern engineering demands customized alloy specifications. By supplying cold-rolled sheets that are readily formed and welded without sensitization, factories help customers optimize production cycles and reduce rework costs.
Global suppliers align production processes with strict regulatory frameworks, including ASTM A240, EN 10028-7, and JIS G4305. This alignment simplifies international certification and ensures reliability in highly regulated markets.
Specific market conditions dictate localized selections of 304L stainless steel sheet thicknesses, finishes, and dimensional tolerances:
A Leading Expert in Coiled Tubes, Polishing Tubing, and Seamless Pipe Fabrication from China
At Liaocheng Sihe Stainless Steel Material Ltd, we operate six highly automated production lines designed to deliver stainless steel coiled tubes, capillary pipes, and custom processing services. We conform strictly to standards including GB, ASTM, ASME, JIS, and EN. Our processing portfolio encompasses austenitic grades (304/304L, 316L, 321, 317L, 309S, 310S) and high-performance alloys (Duplex 2205, Super Duplex 2507, Incoloy 800/825, Inconel 625).
Our facility incorporates world-class bright annealing technology, enabling online thermal treatment of stainless steel products to maintain a clean, oxidation-free surface. All products undergo a rigorous testing sequence to verify their mechanical integrity prior to dispatch, including flaring, flattening, 100% tensile, hardness, hydrostatic, and air tightness tests.
We deliver custom-fabricated products designed for direct integration into challenging engineering systems.
Our facility supports specialized dimensional tailoring for various applications, offering custom coiled formats in diameters ranging from 6.35 mm to 19 mm. Our secondary processing services include precision laser cutting, beveling, mechanical shearing, and protective surface treatments, helping clients streamline their assembly processes.
Our core capabilities include:
Providing reliable material solutions across a wide range of global industrial fields.
Optimized heat-transfer tubes that resist scaling and localized pitting under elevated thermal loads.
Coiled and straight tubes designed for refrigeration loops, ensuring gas confinement and structural ductility at extreme low temperatures.
Materials constructed to resist intergranular corrosion, making them suitable for organic acids and high-pressure process pipelines.
Easily cleaned surfaces that prevent biological contamination, conforming to strict hygiene and regulatory protocols.
High-precision capillary tubing and custom components for sterile dispensing, fluid handling, and bioreactor structures.
Structural elements engineered for steam loops, feedwater pre-heaters, and modern concentrated solar plants.
How our manufacturing lines employ advanced thermal and verification procedures to secure process consistency.
Production reliability begins with raw materials. At Liaocheng Sihe, we use quality melting stocks processed using AOD (Argon Oxygen Decarburization) refining to ensure close control over trace element levels. We use cold rolling and multi-pass drawing techniques to produce sheets, plates, and tubes with precise dimensional tolerances and smooth surface finishes.
A critical stage in our processing line is the online bright annealing thermal cycle. Traditional open annealing processes result in oxidation, which requires acid cleaning (pickling) that can dull the surface finish. By utilizing a controlled, dry hydrogen-nitrogen atmosphere during annealing, we heat the steel past its recrystallization temperature (between 1040°C and 1150°C) and quickly cool it. This preserves a bright, smooth finish and ensures the chromium remains in solid solution, helping maximize corrosion resistance.
Every batch of 304L stainless steel products undergoes a series of mandatory quality verification procedures to confirm structural integrity and compliance with design parameters:
Answers to common technical, commercial, and processing queries regarding 304L stainless steel sheets and tubes.
Explore our full line of specialized stainless steel plates, welded pipes, and precision coiled tubing solutions.
