Comparaison complète des normes de fixations mondiales. Comprendre les normes DIN, ISO, ASTM, ANSI et BS pour boulons, écrous, vis et rondelles dans le commerce international.
Understanding Fastener Standards Systems
Different regions use different fastener standards, which can cause confusion in international trade: DIN (Deutsche Industrie Norm): German standard, widely used in Europe and adopted internationally. Now largely harmonized with ISO standards. ISO (International Organization for Standardization): Global standard, adopted by most countries. ISO standards are the most widely recognized internationally. ASTM (American Society for Testing and Materials): American standard, primarily used in North America but recognized worldwide. ANSI (American National Standards Institute): Coordinates American standards, often adopts ASME/ANSI standards for fasteners. BS (British Standards): British standard, now largely aligned with European EN standards.
Head Marking Comparison
Head markings indicate fastener grade and manufacturer: Metric Hex Bolts (ISO/DIN): - 8.8: Two radial lines below grade marking - 10.9: Three radial lines - 12.9: Three radial lines with higher contrast Inch Hex Bolts (ASTM/ANSI): - Grade 5: Three radial lines - Grade 8: Six radial lines - Grade ASTM A325: 'A325' marking Understanding markings helps verify fastener grade at delivery.
| Metric Grade | Tensile Strength (MPa) | Equivalent ASTM Grade | Head Marking |
|---|---|---|---|
| 4.8 | 400 | Grade 2 | None or 4.8 |
| 8.8 | 800 | Grade 5 | 8.8 |
| 10.9 | 1000 | Grade 8 | 10.9 |
| 12.9 | 1200 | Grade B | 12.9 |
Thread Standards: Metric vs UNC/UNF
Thread standards differ between metric and inch systems: Metric Threads (ISO/DIN): - Designation: M + nominal diameter (e.g., M10) - Thread pitch: Distance between threads (e.g., M10x1.5) - Angle: 60 degrees Inch Threads (UNC/UNF/UNEF): - UNC: Unified National Coarse (standard for general use) - UNF: Unified National Fine (higher strength applications) - UNEF: Unified National Extra Fine (special applications) - Thread count: Threads per inch (e.g., 3/4"-10 UNC) China manufacturers typically produce metric threads as standard but can produce UNC/UNF upon request.
Common Standard Equivalents
Common fastener standards and their equivalents: Hex Bolts: - DIN 933 = ISO 4017 (full thread) - DIN 931 = ISO 4014 (partial thread) - ASTM A325 = ISO 4014 (high strength) Hex Nuts: - DIN 934 = ISO 4032 (standard hex nut) - DIN 985 = ISO 10511 (nylon insert lock nut) Washers: - DIN 125 = ISO 7089 (flat washer) - DIN 127 = ISO 7092 (spring lock washer) When ordering, specify the standard you require - most Chinese manufacturers can produce to any standard specification.