321 Stainless Steel Seamless Tube
As one of the leading 321 stainless steel seamless tube manufacturers and suppliers in China, we warmly welcome you to wholesale 321 stainless steel seamless tube for sale here from our factory. All customized products are with high quality and competitive price. Also, OEM service is available.
- Product Introduction
Product Overview
Grade 321 Stainless Steel Seamless Tubes are premium heat-resistant austenitic stainless steel tubular products engineered for high-temperature service and demanding industrial environments. Manufactured with precision through advanced cold drawing and solution annealing processes, these tubes deliver exceptional dimensional accuracy, superior surface quality, and reliable mechanical stability under continuous operating temperatures up to approximately 870°C.
The addition of titanium as a stabilizing element prevents chromium carbide precipitation during welding and prolonged exposure to elevated temperatures. This specialized metallurgical composition provides outstanding resistance to intergranular corrosion, making these seamless tubes the preferred material for critical applications in petrochemical processing, power generation, aerospace, heat exchangers, and chemical manufacturing industries.
Technical Specifications
|
Parameter |
Specification Details |
|
Material Grades |
ASTM TP321, UNS S32100, EN 1.4541, DIN X6CrNiTi18-10 |
|
Manufacturing Process |
Cold Drawn, Cold Rolled, Hot Finished |
|
Outside Diameter (OD) |
6 mm to 630 mm |
|
Wall Thickness (WT) |
0.5 mm to 50 mm |
|
Length |
Up to 12 meters, fixed lengths, or customized cut lengths |
|
Surface Finishes |
Annealed & Pickled (AP), Bright Annealed (BA), Polished, Mirror Finish, Hairline |
|
Executive Standards |
ASTM A213, ASTM A269, ASTM A312, EN 10216-5, DIN 17458, JIS G3463, GB/T 14975 |
|
End Configurations |
Plain Ends, Beveled Ends, Threaded Ends |
Chemical Composition
|
Element |
Content (%) |
|
Carbon (C) |
≤ 0.08 |
|
Silicon (Si) |
≤ 1.00 |
|
Manganese (Mn) |
≤ 2.00 |
|
Phosphorus (P) |
≤ 0.045 |
|
Sulfur (S) |
≤ 0.030 |
|
Chromium (Cr) |
17.00 – 19.00 |
|
Nickel (Ni) |
9.00 – 12.00 |
|
Titanium (Ti) |
≥ 5 × C, Max. 0.70 |
|
Iron (Fe) |
Balance |
Key Product Features
Titanium Stabilization: Alloyed with titanium to bind carbon and prevent harmful carbide precipitation at grain boundaries during high-temperature exposure.
Intergranular Corrosion Resistance: Exhibits superior resistance to intergranular attack, particularly after welding or in the sensitization temperature range.
High-Temperature Strength: Maintains structural integrity, creep resistance, and mechanical stability under continuous thermal stress up to 870°C.
Oxidation Resistance: Resists scale formation and surface degradation in aggressive oxidizing atmospheres.
Excellent Weldability: Can be easily welded using standard fusion and resistance welding techniques without requiring mandatory post-weld annealing for most applications.
Superior Dimensional Control: Cold-drawn production ensures tight outer diameter and wall thickness tolerances, reducing assembly difficulties.
Smooth Surface Quality: Internal and external surfaces are free from defects, optimizing fluid flow characteristics and minimizing friction losses.
Manufacturing Process
The production of high-integrity stainless steel seamless tubes follows a stringent, monitored workflow:
Raw Material Inspection: Selection of premium certified stainless steel billets verified for chemical purity.
Hot Piercing: Heating the billet and piercing it through rotary piercing mills to form a hollow shell.
Cold Drawing / Cold Rolled: Processing the hollow tube at room temperature to achieve precise dimensions and enhanced mechanical properties.
Solution Annealing: Heat treatment at temperatures exceeding 1050°C followed by rapid quenching to dissolve carbides and restore optimal corrosion resistance.
Pickling and Passivation: Chemical cleaning to remove surface scale and foster a passive chromium oxide protective layer.
Straightening: Mechanical straightening to meet straightness tolerances across the entire tube length.
Non-Destructive Testing: Rigorous internal testing including ultrasonic and eddy current examinations to detect hidden flaws.
Dimensional Inspection: Verification of outer diameter, wall thickness, ovality, and length.
Marking and Packaging: Application of traceable identification markings and secure export packaging.
Quality Inspection and Testing
Every production batch undergoes comprehensive testing regimens to comply with international quality standards:
Positive Material Identification (PMI)
Hydrostatic Pressure Testing
Eddy Current Testing
Ultrasonic Flaw Detection
Pneumatic / Air Underwater Testing
Spectrochemical Analysis
Tensile and Yield Strength Testing
Rockwell and Brinell Hardness Testing
Flattening and Flaring Tests
Intergranular Corrosion Testing (Strauss Test or Huey Test)
Visual and Dimensional Verification
Industrial Applications
Grade 321 seamless stainless steel tubing is engineered for high-demand thermal, structural, and corrosive environments across multiple sectors:
Petrochemical Plants: Process piping, fractionator columns, and high-temperature transfer lines.
Power Generation: Superheater tubes, boiler components, and steam headers.
Heat Exchangers: Tubular heat exchangers, condensers, and recuperators operating in thermal cycling conditions.
Aerospace Industry: Exhaust manifolds, aircraft engine casings, and high-temperature ducting systems.
Chemical Processing: Reaction vessels, acid lines, and catalyst recovery tubes.
Refining Facilities: Catalytic cracking units and sulfur recovery systems.
Automotive Engineering: High-performance exhaust systems and emission control components.
Marine Engineering: Exhaust lines and high-temperature saltwater service structures.
Packaging and Logistics
To guarantee safe global transit and prevent mechanical damage or environmental degradation during ocean and land shipping, standard export packaging options include:
Plastic protective caps fitted on both ends of each tube to shield bevels and threads.
Individual waterproof plastic film wrapping for moisture protection.
Bundling with durable steel straps secured into robust hexagonal or square bundles.
Woven plastic outer protection bags for bundled tubes.
Heavy-duty fumigated wooden boxes and crating for fragile or precision-finished items.
Customized steel frame packaging for oversized or heavy-gauge industrial orders.
FAQ
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