Product Overview This product is a high-strength fully threaded hex head bolt manufactured from medium carbon steel (Grade 8.8) or alloy steel (Grade 10.9), conforming to DIN 933 / ISO 4017 dimensional standards. The bolt features a standard hexagon head and full-length metric thread, with M16 × 2.0 as the flagship size. The zinc-plated finish provides reliable corrosion protection for general industrial, structural, and outdoor applications. The product is available in Grade 8.8 and Grade 10.9 per ISO 898-1 — the two most widely specified high-strength property classes for steel structures, machinery, and infrastructure projects across the Middle East and Central Asia. Product Type & Design Feature Description Product Type High-Strength Hex Head Bolt / Fully Threaded Hex Bolt Head Type Standard hexagon head Thread Configuration Full thread (DIN 933 / ISO 4017) Thread Direction Right-hand (left-hand available on request) Thread Tolerance 6g (metric) The fully threaded design eliminates the unthreaded shank, allowing the bolt to be used in a wider range of grip lengths and enabling full thread engagement with the nut regardless of the clamped thickness. This is particularly advantageous for structural connections with variable plate thicknesses and applications where the bolt must be cut to length on site. Material & Strength Grades Grade Material Tensile Strength (min.) Yield Strength (min.) Hardness Typical Applications 8.8 Medium carbon steel (45#, 10B21), quenched & tempered ≥800 MPa ≥640 MPa 250–320 HB Steel structures, machinery, general connections 10.9 Alloy steel (35CrMo, 40Cr, SCM435), quenched & tempered ≥1,040 MPa ≥940 MPa 320–380 HV Heavy machinery, structural steel, high-load connections Grade 8.8 bolts achieve a minimum tensile strength of 800 MPa and yield strength of 640 MPa, with the "8" representing approximately 1/100 of the minimum tensile strength in MPa and the ".8" indicating a yield-to-tensile ratio of 0.8. Grade 10.9 bolts provide 1,040 MPa minimum tensile strength and 940 MPa minimum yield strength, with the ".9" indicating a yield-to-tensile ratio of 0.9. The 8.8 grade is the most widely specified high-strength bolt class for general structural steel and machinery. The 10.9 grade provides approximately 30% higher tensile strength and is specified for heavy-load structural connections, automotive components, and high-pressure equipment. Standards & Specifications Parameter Details Product Type High-Strength Hex Head Bolt / Fully Threaded Standard DIN 933 / ISO 4017 / GB/T 5783 / DIN 931 / ISO 4014 Thread Size M16 × 2.0 (standard); M6–M36 available Length Range 16 mm – 300 mm (customizable) Thread Type Metric coarse (M) / Metric fine / UNC / UNF / BSW Thread Tolerance 6g (metric) Surface Finish Zinc Plated (Blue-White / Clear / Yellow) Material Carbon steel: 45#, 10B21; Alloy steel: 35CrMo, 40Cr, SCM435 DIN 933 specifies fully threaded hexagon head bolts with metric coarse threads, and is functionally equivalent to ISO 4017. Both standards cover product grades A and B. The M16×2.0 size is the most common metric coarse thread for structural and industrial applications in the GCC. Key Dimensions (M16, DIN 933 / ISO 4017) Parameter Dimension Thread (d) M16 Thread Pitch (P) 2.0 mm Width Across Flats (s) 24.0 mm Width Across Corners (e, min.) 26.75 mm Head Height (k) 10.0 mm Thread Length Full thread (nominal length) All dimensions are in accordance with DIN 933 / ISO 4017 standards. Mechanical Properties (Reference) Size Grade Tensile Strength (MPa) Yield Strength (MPa) Proof Load (MPa) Hardness M16 8.8 800 640 580 250–320 HB M16 10.9 1,040 940 830 320–380 HV M20 8.8 800 640 580 250–320 HB M20 10.9 1,040 940 830 320–380 HV M24 8.8 800 640 580 250–320 HB M24 10.9 1,040 940 830 320–380 HV For Grade 8.8 in sizes M5–M16, the minimum proof load is 580 MPa, while Grade 10.9 achieves 830 MPa minimum proof load in the same size range. The Rockwell C hardness for Grade 10.9 typically ranges from 32 to 36 HRC per relevant standards. Surface Finish & Corrosion Protection Finish Coating Thickness Salt Spray Resistance Recommended Environment Zinc Plated (Blue-White) 8–12 μm 72–144 hours Indoor, general industrial Zinc Plated (Yellow) 8–12 μm 96–168 hours Outdoor, moderate corrosion Zinc Plated (Clear) 5–8 μm 48–96 hours Indoor, temporary protection Hot-Dip Galvanized (HDG) 45–85 μm 500–1,500+ hours Outdoor, coastal, marine Dacromet (Zinc-Flake) 5–12 μm 600–1,500+ hours Coastal, offshore, high-corrosion Zinc plating provides sacrificial (cathodic) protection to the underlying steel. The zinc coating corrodes preferentially, protecting the steel substrate from rust. Standard blue-white zinc plating provides good corrosion protection for indoor and general industrial applications. Important note for Grade 10.9: Electroplated high-strength bolts (Grade 10.9 and above) are susceptible to hydrogen embrittlement during the plating process. Per ISO 4042, fasteners with hardness above 320 HV require post-coating baking at 190–220°C for 4–24 hours to drive off hydrogen and prevent delayed brittle fracture. The baking must be performed within a few hours of plating to be effective. For critical or coastal applications, Dacromet (zinc-flake) coating is recommended as an alternative that eliminates hydrogen embrittlement risk entirely while providing superior corrosion resistance. Torque Specifications Size Grade 8.8 Tightening Torque (N·m) Grade 10.9 Tightening Torque (N·m) M10 48 65 M12 86 117 M16 210 285 M20 410 560 M24 710 970 Torque values assume μ = 0.12–0.14 (zinc-plated, unlubricated). For lubricated or coated fasteners, adjust torque accordingly. Applications High-strength hex head bolts are widely used across industries: Steel Structure & Construction — Beam-to-column connections, bracing, column base anchoring, steel frame assembly Oil & Gas Facilities — Pipe racks, pressure vessel supports, structural connections in petrochemical plants Power Generation — Turbine mounting, generator anchoring, transmission tower connections Heavy Machinery — Presses, cranes, mining equipment, construction machinery Desalination & Marine — Structural fastening in coastal and offshore installations (with HDG or Dacromet coating) Bridge & Infrastructure — Girder connections, expansion joint fastening, guardrail mounting General Industrial — Equipment assembly, frame connections, adjustment rods Grade 8.8 bolts are the standard choice for general steel structure and machinery applications, while Grade 10.9 is specified for heavy-load structural connections where higher tensile strength and preload are required. Quality Assurance All products are manufactured under strict quality control procedures in accordance with ISO 898-1 (mechanical properties of fasteners), DIN 933 / ISO 4017 (dimensional standards), and ISO 4042 (electroplated coatings). 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. For Grade 10.9 bolts, tensile testing, hardness testing, and hydrogen embrittlement relief baking verification are performed on each production batch. Packaging & Customization Export Packing: Carton / wooden case / steel pallet Domestic Packing: Standard corrugated box / bag OEM/ODM: Available — custom sizes, thread types, materials, strength grades, and surface finishes can be produced according to drawings or samples MOQ: Negotiable Ordering Information To place an order or request a quotation, please specify: Product type — Hex head bolt (fully threaded / partially threaded) Standard — DIN 933 / ISO 4017 / DIN 931 / ISO 4014 / GB/T 5783 Material — Carbon steel (45#, 10B21) / Alloy steel (35CrMo, 40Cr, SCM435) Strength grade — 8.8 / 10.9 Thread size and pitch — e.g., M16 × 2.0 (standard) Length — Specify total length (e.g., 40 mm, 60 mm, 80 mm) Surface finish — Zinc plated (specify color) / HDG / Dacromet / Plain Quantity — With any tolerance for over/under shipment Certification — EN 10204 3.1 MTC / ISO 898-1 compliance / SASO (for Saudi Arabia) / EAC CoC (for Kazakhstan) Special requirements — Thread tolerance, marking, packaging, hydrogen embrittlement baking record (for zinc-plated 10.9)