Carbon Steel Hex Nut — Factory Direct Supplier | Huaxia-Steel
Carbon steel hex nuts are fundamental fastening components used across virtually every industrial application involving bolted connections. As a factory-direct manufacturer, Huaxia-Steel produces hex nuts to ASME B18.2.2, DIN 934, ISO 4032, and GB/T 6170 standards, covering sizes from M3 to M64 (1/8″ to 2-1/2″). Our hex nuts are available in strength grades 4, 5, 6, 8, and 10, with surface treatments including plain, galvanized, black oxide, and zinc-plated. Full material certification and traceability ensure compliance with international fastener standards.
Product Overview
Hex nuts are six-sided internally threaded fasteners designed to mate with external threaded bolts, screws, or studs. When tightened, they create a clamping force that holds assembled components together. Carbon steel hex nuts are the most common nut type due to their excellent strength-to-cost ratio, wide availability, and compatibility with standard bolt grades. They are used in construction, machinery, automotive, pipeline flanges, structural steel, and general engineering applications.
Huaxia-Steel manufactures hex nuts using both cold-heading (for sizes M3–M20) and hot-forging (for sizes M20–M64) processes. Cold-heading produces nuts with superior dimensional accuracy and surface finish, while hot-forging is used for larger sizes where the material requires heating for proper forming. After forming, nuts are tapped (internal threading), heat-treated (for higher strength grades), and surface-finished according to customer specifications.
Specifications & Dimensions
Standard Hex Nuts — DIN 934 / ISO 4032
| Size | Width Across Flats (mm) | Width Across Corners (mm) | Height (mm) | Thread Pitch (mm) |
|---|---|---|---|---|
| M3 | 5.5 | 6.0 | 2.4 | 0.5 |
| M4 | 7.0 | 7.7 | 3.2 | 0.7 |
| M5 | 8.0 | 8.8 | 4.0 | 0.8 |
| M6 | 10.0 | 11.1 | 5.0 | 1.0 |
| M8 | 13.0 | 14.4 | 6.5 | 1.25 |
| M10 | 16.0 | 17.8 | 8.0 | 1.5 |
| M12 | 18.0 | 20.0 | 10.0 | 1.75 |
| M16 | 24.0 | 26.8 | 13.0 | 2.0 |
| M20 | 30.0 | 33.5 | 16.0 | 2.5 |
| M24 | 36.0 | 40.2 | 19.0 | 3.0 |
| M30 | 46.0 | 51.3 | 24.0 | 3.5 |
| M36 | 55.0 | 61.3 | 29.0 | 4.0 |
| M42 | 65.0 | 72.5 | 34.0 | 4.5 |
| M48 | 75.0 | 83.6 | 38.0 | 5.0 |
Heavy Hex Nuts — ASME B18.2.2
| NPS (in) | Width Across Flats (mm) | Height (mm) | Approx Weight (kg/100) |
|---|---|---|---|
| 1/2 | 22.2 | 12.7 | 0.40 |
| 5/8 | 27.0 | 15.9 | 0.75 |
| 3/4 | 31.8 | 19.1 | 1.25 |
| 7/8 | 36.5 | 22.2 | 1.90 |
| 1 | 41.3 | 25.4 | 2.80 |
| 1-1/8 | 46.0 | 28.6 | 3.90 |
| 1-1/4 | 50.8 | 31.8 | 5.20 |
| 1-1/2 | 60.3 | 38.1 | 8.50 |
| 2 | 79.4 | 50.8 | 18.50 |
Strength Grades & Mechanical Properties
| Grade | Proof Load (MPa) | Hardness (HRC) | Hex Nut Standard | Matching Bolt Grade |
|---|---|---|---|---|
| 4 | — | — | DIN 934 | Grade 4.6 |
| 5 | 510 | 22–32 | ASME B18.2.2 | SAE Grade 5 / A325 |
| 6 | 600 | 25–35 | DIN 934 | Grade 6.8 |
| 8 | 830 | 28–34 | ASME B18.2.2 | SAE Grade 8 / A490 |
| 10 | 940 | 28–38 | DIN 934 | Grade 10.9 |
| 12 | 1100 | 31–40 | DIN 934 | Grade 12.9 |
Available Materials & Surface Treatments
Materials
- Low carbon steel (C≤0.25%): Grades 4.6, 5.6 — for general-purpose applications
- Medium carbon steel (C 0.25–0.55%): Grades 5, 8, 8.8 — heat-treated for higher strength
- Alloy steel (Cr-Mo, Cr-Ni): Grades 10.9, 12.9 — for high-stress structural connections
- ASTM A194 Grade 2H: For high-temperature and high-pressure flange applications
Surface Treatments
| Treatment | Corrosion Resistance | Color | Temperature Limit |
|---|---|---|---|
| Plain (oil) | Minimal | Black/self | N/A |
| Black oxide | Low (indoor) | Black | 200°C |
| Zinc plating (clear) | Medium (96h salt spray) | Silver | 200°C |
| Zinc plating (yellow) | Medium-High (168h) | Yellow/gold | 200°C |
| Hot-dip galvanized | High (500h+) | Silver-gray | 300°C |
| PTFE coated | Very High (1000h+) | Black/white | 200°C |
| Dacromet | Very High (1200h+) | Silver | 300°C |
Manufacturing Standards
- ASME B18.2.2: Nuts for General Applications (Imperial)
- DIN 934: Hexagon Nuts (Metric, standard height)
- DIN 6915: Hexagon Nuts for High-Strength Structural Bolting
- ISO 4032: Hexagon Regular Nuts (Style 1)
- ISO 4033: Hexagon High Nuts (Style 2)
- GB/T 6170: Hexagon Nuts (Chinese national standard)
- ASTM A563: Carbon and Alloy Steel Nuts (Imperial grades)
- ASTM A194: Nuts for Bolts for High-Pressure and High-Temperature Service
Applications
- Structural steel connections (A325/A490 bolt and nut assemblies)
- Pipeline flange bolting (B7 studs with 2H nuts)
- Machinery and equipment assembly
- Automotive and truck chassis fastening
- Construction scaffolding and formwork
- Power transmission tower connections
- Pressure vessel and boiler assembly
- General engineering and maintenance
Quality Assurance
- Chemical composition verification via spectrometer per heat lot
- Mechanical testing: proof load testing per ASTM F606 or ISO 898-2
- Hardness testing: Rockwell (HRC) or Vickers (HV) per grade requirement
- Thread inspection: GO/NO-GO thread plug gauges, 100% for critical applications
- Dimensional inspection: width across flats, height, thread pitch diameter
- Surface treatment verification: coating thickness (micrometer), salt spray test
- Visual inspection: no cracks, burrs, or surface defects
- 100% magnetic particle inspection available for high-strength grades
- Material Test Certificate per EN 10204 3.1 with heat number traceability
Packaging & Shipping
- Small sizes (M3–M8): polyethylene bags, 1000 pcs per bag, then carton-packed
- Medium sizes (M10–M20): 500 pcs per bag, palletized for shipping
- Large sizes (M24–M64): individual packaging or 50–100 pcs per box
- Export packaging: wooden pallets with shrink wrap, ISPM-15 compliant
- Labeling: size, grade, standard, surface treatment, quantity, heat number, PO number
- VCI paper and desiccant for sea freight to prevent corrosion
- Container loading photos and detailed packing list provided
Conclusion
Carbon steel hex nuts are essential fastening components that demand precise manufacturing and consistent quality. Huaxia-Steel’s factory-direct production covers the full range of sizes, grades, and surface treatments, with rigorous quality control ensuring every nut meets international standards. Whether you need standard DIN 934 hex nuts for general engineering or heavy hex nuts for structural bolting, our competitive pricing and reliable delivery make us your trusted supply partner. Contact us today for a quotation — we respond within 24 hours.
