Guide complet pour inspecter la qualité des fixations. Couvre les vérifications dimensionnelles, les tests de dureté, l'épaisseur du revêtement et les services d'inspection tiers.
Why Quality Inspection Matters
Fastener failures cause serious safety incidents and financial losses: - Structural failures: 23% of construction failures involve fastener issues - Equipment damage: Substandard fasteners cause machinery breakdowns - Liability: Using non-compliant fasteners can create legal liability - Cost: Failed fasteners require expensive rework and delays TradeGo Fasteners operates ISO 9001:2015 certified quality management with mandatory inspection before shipment. Third-party inspection available through SGS, Bureau Veritas, or Intertek.
Visual Inspection Checklist
Visual inspection is the first line of quality verification: 1. Surface Defects: Check for cracks, seams, laps, or burrs 2. Head Defects: Verify proper head formation, no flash or fins 3. Thread Defects: Check for torn threads, stripped threads, or die lines 4. Coating Quality: Verify uniform coating, no bare spots or peeling 5. Marking Verification: Confirm grade marking matches specifications 6. Packaging: Check for proper labeling and moisture protection Use 10x magnification for detailed thread inspection.
Dimensional Inspection
Key dimensions to verify: 1. Overall Length: Use calipers, measure from under head to thread end 2. Thread Pitch: Use thread gauge or measure with calipers 3. Across Flats (AF): Hex dimension, verify with AF gauge 4. Across Corners (AC): Maximum dimension, verify with calipers 5. Head Height: Verify against standard specifications 6. Washer Thickness: For flat washers, measure with micrometer Acceptance criteria typically ±0.1mm for critical dimensions.
Mechanical Testing
Mechanical properties require specialized testing: 1. Hardness Testing: Use Rockwell or Vickers hardness tester - Carbon steel: HRC 25-45 typical - Case hardened: HRC 58-62 surface 2. Tensile Testing: Break specimen in universal testing machine - Proof load test: Applied load without permanent set - Ultimate tensile strength: Load at failure 3. Torque Testing: Apply torque to failure or specified torque 4. Impact Testing: Charpy V-notch for ductility TradeGo provides mill test certificates (EN 10204 3.1) with each shipment confirming mechanical properties.
Coating Inspection
Coating quality critical for corrosion resistance: 1. Zinc Plating: 8-12 microns typical 2. Hot-Dip Galvanizing: 45-85 microns (ASTM A153) 3. Measurement: Use magnetic or eddy current coating thickness gauge Visual Checks: - No bare spots or dark patches - Uniform metallic appearance - No peeling or flaking - No white rust (storage corrosion) For hot-dip galvanized: Verify complete coverage including thread roots.
Third-Party Inspection Services
For container-scale orders, third-party inspection provides independent verification: Major Inspection Companies: 1. SGS: Largest, global presence, competitive pricing 2. Bureau Veritas: Strong in Africa trade routes 3. Intertek: Fast turnaround available 4. TÜV: Premium positioning, strong in Europe Inspection Levels: - Dimensional inspection only: $150-200/day - Full quality inspection: $300-500/day - Laboratory testing additional: $100-300/sample TradeGo can arrange third-party inspection upon buyer request at buyer expense.