Product Overview Zinc-plated hex head bolts are general-purpose carbon steel fasteners with an electroplated zinc coating for economical corrosion protection. Manufactured to DIN 933 / ISO 4017 / GB/T 5783, these fully threaded bolts are suitable for indoor and general outdoor applications across construction, automotive, furniture, and light industrial assembly. Available in bright zinc (blue-white) and color zinc finishes, with strength grades 4.8 and 8.8 as standard. Ready stock in common metric sizes. Key Specifications Parameter Specification Material Carbon steel (Q235 / 45# / 10B21) Strength Grade 4.8 (standard); 8.8 available Standard DIN 933 / ISO 4017 / GB/T 5783 Thread Metric coarse (M), full thread Surface Finish Bright zinc (blue-white) / Color zinc Thread Diameter M3 – M30 Length Range 8 mm – 200 mm Head Type Hexagon head Product Grade A Mechanical Properties (ISO 898-1 / GB/T 3098.1) Property Grade 4.8 Grade 8.8 Minimum Tensile Strength (Rm) 400 MPa 800 MPa Minimum Yield Strength (Rp0.2) 320 MPa 640 MPa Core Hardness 13–22 HRC 22–32 HRC Elongation After Fracture (A min) 22% 12% Material Condition As-rolled / normalized Quenched and tempered Grade 4.8 bolts are suitable for light-duty general fastening where high tensile strength is not required. Grade 8.8 bolts are quenched and tempered for structural and mechanical joints requiring higher load-bearing capacity. Surface Finish: Bright Zinc vs. Color Zinc Bright zinc (blue-white) is the standard electroplated finish, providing a clean, bright appearance with moderate corrosion resistance. It is suitable for indoor use and short-term outdoor exposure. Typical coating thickness is 5–8 μm. Color zinc (yellow/iridescent chromate conversion coating) offers improved corrosion resistance compared to bright zinc. Per GB/T 5267.4, the minimum local coating thickness requirements are: General purpose: ≥8 μm — passing ≥96 hours neutral salt spray (NSS) without red rust High corrosion resistance: ≥12 μm — passing ≥200 hours NSS without red rust Salt spray testing follows GB/T 10125-2021 / ISO 9227 with 5% NaCl solution at 35 ± 2 °C. For electroplated high-strength bolts (Grade 8.8 and above), dehydrogenation baking within 24 hours of plating is strongly recommended to prevent hydrogen embrittlement. Standards & Compliance These bolts conform to DIN 933 (fully threaded hexagon head screws), ISO 4017 (international equivalent, product grades A and B), and GB/T 5783. Dimensional interchangeability across these standards ensures compatibility with international equipment and assemblies. Applications Zinc-plated hex bolts are specified for general-purpose fastening across multiple industries: Construction — steel frames, scaffolding, general building assembly Automotive — chassis components, brackets, and non-critical structural joints Furniture — metal frame assembly and hardware fastening Machinery — general equipment assembly and maintenance Electrical & HVAC — enclosure mounting and ductwork fastening Outdoor structures — with color zinc or Grade 8.8 for enhanced durability Available Sizes Thread (M) Pitch (mm) Common Lengths Hex Across-Flats (s) M6 1.0 16 – 80 mm 10 mm M8 1.25 16 – 100 mm 13 mm M10 1.5 20 – 120 mm 17 mm M12 1.75 25 – 150 mm 19 mm M16 2.0 30 – 200 mm 24 mm M20 2.5 40 – 200 mm 30 mm Full range available from M3 through M30. Custom lengths, thread pitches, and head configurations available on request. Ordering Information Thread sizes: M3–M30 standard Lengths: 8–200 mm standard; custom lengths available Strength grades: 4.8 (standard); 8.8 available Finishes: Bright zinc (blue-white) / Color zinc Fastener sets: Available as bolt only, or complete set with hex nut and washers Packaging: Bulk carton, small box, or customized export packing Documentation: Mill test certificates, salt spray test reports, and material traceability available MOQ: Flexible for wholesale and distributor orders Please inquire for specific size combinations, volume pricing, and lead times. Quality Assurance Each production batch is subject to dimensional inspection and mechanical property testing in accordance with ISO 898-1. Coating thickness is verified per GB/T 5267.4 / ISO 4042. Third-party inspections (SGS, BV, TUV) are available upon request. Material certificates and test reports are available for every shipment.