Stainless Steel Seamless Tube China Manufacturer

Stainless Steel Seamless Tubes (ASTM A269/ASME SA269)

Precision Engineering for Critical Fluid Systems

Metallurgical Composition

UNS S31603/S30400 tubes feature optimized chemistry for thin-wall applications:

• Chromium (Cr): 16.0–18.0% (316) / 18.0–20.0% (304) – Forms passive oxide layer

• Nickel (Ni): 10.0–14.0% (316) / 8.0–10.5% (304) – Stabilizes austenitic structure

• Molybdenum (Mo): 2.0–3.0% (316 only) – Enhances pitting resistance

• Carbon (C): ≤0.03% (316L) / ≤0.08% (304) – Controls carbide precipitation

• Nitrogen (N): ≤0.10% – Increases yield strength without compromising ductility

• Trace Elements: Mn≤2.0%, Si≤0.75%, P≤0.045%, S≤0.030% to minimize inclusion formation

Mechanical Performance

Solution Annealed Condition (1040°C Water Quench):

• Property 316L 304 Test Standard

• Tensile Strength 515–620 MPa 515–720 MPa ASTM A370

• 0.2% Yield Strength 205 MPa min 205 MPa min EN ISO 6892-1

• Elongation (50mm GL) 40% min 40% min ASME SA-450

• Hardness 80 HRB max 80 HRB max ASTM E18

• Impact Toughness 100J @ -196°C 100J @ -196°C ISO 148-1

High-Temp Performance:

• Sustains 150 MPa yield strength @ 400°C

• Oxidation resistance limit: 870°C continuous / 925°C intermittent

Manufacturing Excellence

1. Piercing & Extrusion:

• Billet heating to 1250°C ±15°C in induction furnaces

• Mannesmann piercing with 8:1 reduction ratio

• Cold drawing with 35–80% area reduction using carbide dies

2. Surface Perfection:

• Electropolishing to Ra ≤0.4 μm (SEMI F20 Class B)

• Pickling in HNO₃/HF bath to remove scale (ASTM A380)

• Passivation per ASTM A967 Method 3 (citric acid)

3. Critical Testing:

• 100% Eddy Current Testing (ASTM E426) detects flaws >0.125mm deep

• Hydrostatic testing at 300 bar (30% above ASME B31.3 requirement)

• PMI verification via handheld XRF (Cr/Ni/Mo ratio ±0.5%)

Industry-Specific Applications

Semiconductor Manufacturing:

• Ultra-high purity gas delivery (O₂/N₂/Ar) with ≤0.1 μg/m² particle shedding

• Compatible with VCR/VCO fittings for vacuum-tight systems

• Outgassing rate <1×10⁻⁹ Torr·L/sec·cm² (SEMI F20 validated)

Medical Gas Systems:

• ISO 15001 compliant for O₂ service (hydrocarbon-free surfaces)

• Cleanroom assembly per ISO 13485 with 0.1μm particle control

• Validated for USP Class VI biocompatibility

Energy Instrumentation:

• Nuclear reactor pressure sensors (ASME III Class 1)

• Subsea control umbilicals with 25-year design life (API 17E)

• Hydrogen compatibility per ISO 11114-4

Certifications & Compliance

Quality Systems: ISO 9001:2015 / PED 2014/68/EU Category IV

Material Certs: EN 10204 3.2 with full traceability

Industry Standards:

ASTM A269 (Chemical/Mechanical)

ASME SB269 (Pressure Design)

DIN 17456 (Dimensional Tolerances)

Special Testing:

Intergranular Corrosion Test (ASTM A262 Practice E)

Ferrite Content Verification (FN 5-12 per ASTM E562)

Salt Spray Resistance >1000hrs (ISO 9227)

Technical Differentiation

1. Thin-Wall Capability:

• Wall thickness range: 0.5mm–10mm (±0.05mm tolerance)

• Concentricity deviation <0.015mm (laser micrometer verified)

2. Specialized Variants:

• Pharmaceutical Grade: Double-certified 316L with Ra≤0.15μm ID

• Cryogenic Service: LN₂ shock-tested to -269°C (ASTM A632)

• High-Pressure Design: SCH 160 tubes rated for 850 bar @ 20°C

3. Failure Prevention:

Stress corrosion cracking (SCC) immunity:

• Cl⁻ limit: 2,000 ppm @ 60°C (vs. 500 ppm for welded tubes)

• Residual stress <20% yield strength (X-ray diffraction verified)

Global Supply Chain Data:

Parameter Specification

Lead Time 8–12 weeks (custom sizes)

Standard Sizes OD 1/8"–6" │ WT 0.028"–0.5"

Packaging PVC-capped ends │ VCI paper

Traceability QR code per tube segment

Compliance Markings Laser-etched ASTM/Heat No.