Product Overview This product is a high-strength hexagon nut manufactured to GB/T 6170-2015 (Type 1 Hexagon Nuts) , available in Property Classes 8, 10, and 12 per ISO 898-2. The nut features a standard hexagonal profile with metric coarse threads and is designed to pair with high-strength bolts in Grade 8.8, 10.9, and 12.9 for structural, machinery, and industrial applications. The GB/T 6170-2015 standard specifies Type 1 hexagon nuts with thread sizes from M1.6 to M64, covering property classes 6, 8, 10, A2-50, A2-70, A4-50, A4-70, CU2, CU3, and AL4, with product grades A (for D ≤ 16 mm) and B (for D > 16 mm). The standard is a modified adoption of ISO 4032:2012, ensuring international dimensional compatibility. Product Type & Design Feature Description Product Type Type 1 Hexagon Nut / High-Strength Hex Nut Profile Standard hexagonal (six-sided) Thread Configuration Metric coarse thread (standard); fine thread available Thread Direction Right-hand (left-hand available on request) Product Grade A (D ≤ 16 mm) / B (D > 16 mm) Standard GB/T 6170-2015 (modified adoption of ISO 4032:2012) Type 1 hexagon nuts are the most fundamental and widely used nut configuration, offering six-sided wrench engagement for reliable torque transmission and full thread engagement with the mating bolt. The hexagonal profile allows tightening from any of six positions, making these nuts suitable for both manual and automated assembly. Material & Strength Grades Grade Material Proof Load (MPa) Hardness Typical Applications 8 Medium carbon steel (45#, 10B21), quenched & tempered ≥ 800 MPa 250–320 HV Steel structures, machinery, general connections 10 Medium carbon steel / alloy steel, quenched & tempered ≥ 1,040 MPa 320–380 HV Heavy machinery, structural steel, high-load connections 12 Alloy steel (42CrMo, SCM435), quenched & tempered ≥ 1,220 MPa 385–435 HV Critical high-stress structural, bridge connections Grade 8 hex nuts provide a minimum proof load of 800 MPa and are the standard choice for general structural and machinery applications. Grade 10 provides approximately 30% higher proof load and is specified for heavy-load connections. Grade 12 achieves a minimum proof load of 1,220 MPa, matching the tensile strength of Grade 12.9 bolts for maximum-load applications. Critical pairing rule: Nuts must be matched with bolts of corresponding or higher property class. A Grade 8 nut is suitable for Grade 8.8 bolts; a Grade 10 nut for Grade 10.9 bolts; a Grade 12 nut for Grade 12.9 bolts. Using a lower-class nut with a higher-class bolt will result in thread stripping of the nut before the bolt reaches its full load capacity. Standards & Specifications Parameter Details Product Standard GB/T 6170-2015 (Type 1 Hexagon Nuts) International Equivalent ISO 4032:2012 (modified adoption) Thread Standard GB/T 193 (metric coarse) / GB/T 196 (thread dimensions) Thread Sizes M1.6 – M64 (standard); M8–M36 most common Thread Pitch M8×1.25, M10×1.5, M12×1.75, M16×2.0, M20×2.5, M24×3.0, M30×3.5 Thread Tolerance 6H (metric) Surface Finish Plain / Zinc Plated / Hot-Dip Galvanized / Dacromet / Black Oxide Product Grade A (D ≤ 16 mm) / B (D > 16 mm) GB/T 6170-2015 is the Chinese national standard for Type 1 hexagon nuts, with technical requirements including dimensions, mechanical properties, and marking. The standard specifies product grade A for nuts with nominal diameter ≤ 16 mm and product grade B for nuts with nominal diameter > 16 mm. Key Dimensions (Reference — GB/T 6170 / ISO 4032) Thread Size (D) Pitch (P) mm Width Across Flats (s) mm Height (m) mm Product Grade M6 1.0 10.0 5.0 A M8 1.25 13.0 6.5 A M10 1.5 16.0 8.0 A M12 1.75 18.0 10.0 A M16 2.0 24.0 13.0 A M20 2.5 30.0 16.0 B M24 3.0 36.0 19.0 B M30 3.5 46.0 24.0 B M36 4.0 55.0 29.0 B All dimensions are in accordance with GB/T 6170-2015 / ISO 4032:2012 standards. Mechanical Properties (Reference — ISO 898-2) Grade Proof Load (MPa) Hardness (HV) Matching Bolt Class 8 ≥ 800 250–320 8.8 10 ≥ 1,040 320–380 10.9 12 ≥ 1,220 385–435 12.9 Proof load is the maximum load the nut can withstand without permanent deformation. For Grade 8 nuts, the minimum proof load is 800 MPa; for Grade 10, 1,040 MPa; for Grade 12, 1,220 MPa. These values align with the tensile strength requirements of the matching bolt classes. Surface Finish Options Finish Coating Thickness Salt Spray Resistance Recommended Environment Plain — 24–48 hours Temporary, indoor Zinc Plated (Blue-White) 8–12 μm 72–144 hours Indoor, general industrial Hot-Dip Galvanized (HDG) 45–85 μm 500–1,500+ hours Outdoor, coastal, marine Dacromet 5–12 μm 600–1,500+ hours Coastal, offshore, high-corrosion Black Oxide 0.5–1.5 μm 24–96 hours Indoor, machinery, tooling For high-strength Grade 10 and Grade 12 nuts, Dacromet (zinc-flake) coating is recommended over electroplating to eliminate hydrogen embrittlement risk. Hot-dip galvanizing is suitable for Grade 8 nuts in outdoor and coastal applications. Applications High-strength hex nuts are widely used across industries: Steel Structure & Construction — Beam-to-column connections, bracing, column base anchoring, bridge connections Oil & Gas Facilities — Pipe racks, pressure vessel supports, wellhead equipment, pipeline flanges Petrochemical Plants — Reactor vessels, heat exchangers, high-pressure piping Power Generation — Turbine mounting, generator anchoring, transmission tower connections Heavy Machinery — Presses, cranes, mining equipment, construction machinery Wind Energy — Turbine tower flange connections, blade fastening Desalination & Marine — Structural fastening in coastal and offshore installations (HDG or Dacromet coating recommended) Regional insight: High-strength hex nuts are a core product category for Middle East fastener manufacturers. Al-Rashed Fasteners (Saudi Arabia) produces high-strength bolts (Gr 8, 10.9, 12.9) and heavy hex structural bolt and nuts (A325, A325M, BS4395), supplying major projects including Jubail and Yanbu, King Fahd Causeway, Rabigh Makkah Project, and Qasim/Riyadh Transmission Tower. Quality Assurance All products are manufactured under strict quality control procedures in accordance with GB/T 6170-2015, ISO 898-2, and ISO 4032 standards. Quality control steps performed on each production batch: Chemical composition verification of the steel material Proof load testing per ISO 898-2 Hardness testing to confirm the specified property class Thread gauge inspection (go/no-go gauges) for 6H tolerance Visual inspection for surface defects and coating uniformity Marking verification — property class and manufacturer identification Material test certificates (EN 10204 3.1), dimensional inspection reports, hardness test reports, and third-party inspection reports (SGS, BV, CTI) can be provided upon request. Packaging & Customization Export Packing: Carton / wooden case / steel pallet Domestic Packing: Standard corrugated box / plastic bag / bulk carton OEM/ODM: Available — custom sizes, thread types (metric / UNC / UNF / BSW), materials (carbon steel, alloy steel, stainless steel), and surface finishes (zinc plated, HDG, Dacromet, plain) can be produced according to drawings or samples MOQ: Negotiable Ordering Information To place an order or request a quotation, please specify: Product type — Type 1 Hexagon Nut (GB/T 6170) Standard — GB/T 6170-2015 / ISO 4032:2012 Material — Carbon steel (45#, 10B21) / Alloy steel (42CrMo, SCM435) Property class — 8 / 10 / 12 Thread size and pitch — e.g., M16 × 2.0 or M20 × 2.5 Surface finish — Plain / Zinc Plated / HDG / Dacromet / Black Oxide Quantity — With any tolerance for over/under shipment Certification — EN 10204 3.1 MTC / ISO 898-2 compliance / SASO (for Saudi Arabia) / EAC (for Kazakhstan) Special requirements — Thread tolerance, marking, packaging, proof load test reports, etc.