302 is an 18/8 austenitic chromium-nickel alloy optimized for extreme cold forming and high tensile strength after work hardening. With higher carbon (0.15% max) than 304, it achieves:

• 30% higher tensile strength in full-hard condition vs. 304

• Superior fatigue resistance for dynamic load applications

• Retained non-magnetism after moderate cold working

Our pipes comply with ASTM A312, A554, AMS 5560 for seamless/welded construction.

Why Choose Luokaiwei’s 302 Pipes?

Technical Specifications

Table 1: Chemical Composition (Weight %)

Table 2: Mechanical Properties by Condition

Dominant Applications

• Spring Systems:

  • Conical valve springs, clutch torsion springs

  • Surgical instrument forceps (ASTM F899 compliant)

• Fastener Manufacturing:

  • Cold-headed bolts, rivets, precision washers

• Aerospace:

  • Fuel injection lines, actuator sleeves (AMS 5560 certified)

• Consumer Electronics:

  • SIM card ejector pins, hinge mechanisms

• Textile Machinery:

  • High-speed shuttle guides, needle tubes

Luokaiwei’s Precision Manufacturing

1. Material Control:

   • VIM-melted billets (inclusion rating ≤ASTM E45 A1.5)

   • Traceable heats with mill certifications

2. Pipe Formation:

   • Seamless: Multi-stage cold drawing (OD 0.5–100 mm)

   • Welded: Laser/TIG with inert gas shielding (OD 100–300 mm)

3. Heat Treatment:

   • Bright annealing: 1010–1120°C in H₂/N₂ atmosphere

   • Stress relieving: 425°C for critical tolerance parts

4. Finishing:

   • Centerless grinding (OD tolerance ±0.005 mm)

   • Electrolytic polishing for Ra ≤0.1 μm

5. Quality Assurance:

   • 100% eddy current testing (ASTM E309)

   • Salt spray testing: 500+ hours (ASTM B117)

   • Spring fatigue validation (10⁷ cycles)

Design & Fabrication Guidelines

✅ Best Practices:

• Cold Forming:

  • Maximum reduction: 80% per pass (anneal between stages)

  • Bend radius ≥1x OD in annealed state

• Welding (Use Sparingly):

  • Filler: ER308L with 98% Ar + 2% O₂

  • Interpass Temp: ≤150°C to prevent hot cracking

• Machining:

  • Carbide tools with chip breakers

  • Feed rate >0.15 mm/rev to avoid work hardening

⚠️ Critical Restrictions:

• Avoid: Temperatures 425–860°C (sensitization risk)

• Not Recommended: Sulfuric/chloride environments (>40°C)

5 Essential FAQs

Q1: Why choose 302 over 304 for springs?
A: 302’s higher carbon delivers 40% greater yield strength after cold working while maintaining ductility – critical for high-cycle springs.

Q2: Can 302 pipes be used in food contact applications?
A: Limited to non-continuous contact (e.g., machinery parts). For direct food exposure, use 316L with electropolishing.

Q3: Do you supply thin-walled tubes for medical devices?
A: Yes – our specialty:

Q4: How does 302 compare to 17-7PH precipitation hardening steel?

Q5: What certifications do your aerospace-grade pipes carry?
A: Full compliance with:

• AMS 5560 (Seamless Tubing)

• EN 10204 3.2 Material Certificates

• NADCAP AC7110 (Special Processes)

Why Partner with Luokaiwei?

• Specialized Processing:

  • In-house bright annealing furnaces

  • Precision grinding with ±0.002 mm capability

• Testing Rigor:

  • Microhardness mapping (HV0.3)

  • Ferrite scope phase analysis

• Global Logistics:

  • 30-day delivery for standard sizes

  • Vacuum packaging for medical-grade tubes

Order Your High-Performance 302 Pipes Today!
✅ MOQ: 200 kg (standard sizes), 50 kg (medical/aerospace)
✅ Certifications: RoHS, REACH, ISO 13485 (medical)
✅ Custom Services:

• ID/OD honing

• Laser micro-perforation

• Passivation per ASTM A967

Contact Luokaiwei:
📧 sales@luokaiweipipe.com
📱 +86 18912200505