Overview
ISO 4018:2022 - Fasteners - Hexagon head screws - Product grade C specifies the characteristics of steel hexagon head screws with metric coarse pitch threads M5 to M64 in product grade C. The standard covers dimensional data, mechanical property symbols, tolerances and labelling rules to ensure consistent manufacture, inspection and procurement of hexagon head screws used in industrial and construction applications. Where different mechanical or dimensional options are required, property classes and dimensional choices can be taken from ISO 898-1, ISO 888 or ISO 4753.
Key topics and technical requirements
- Scope and material: Steel hexagon head screws, coarse metric threads M5–M64, product grade C.
- Dimensions: Detailed head and thread dimensions provided (Figures and Tables for M5–M64). Rules for shortest and greatest standard lengths (greatest standard length limited to 200 mm unless agreed otherwise).
- Thread and tolerances:
- Thread tolerance position: 8g (general guidance).
- Thread tolerances per ISO 965-1.
- Property classes commonly specified for M5 ≤ d ≤ M39: 4.6, 4.8; for d > M39: to be agreed.
- Surface condition & coatings: “As processed” by default; electroplated coatings (ISO 4042), zinc-flake (ISO 10683) and hot-dip galvanized (ISO 10684) referenced. Other coatings by agreement.
- Surface integrity & acceptance: Surface discontinuities per ISO 6157-1; acceptance inspection per ISO 3269.
- Marking and labelling:
- Product marking as specified in ISO 898-1.
- Package labelling must include ISO 4018 reference, thread size and length, property class, surface finish, manufacturer ID, lot number (ISO 1891-4) and quantity.
- Designation: Follow ISO 8991 designation system (example: Hexagon head screw ISO 4018 – M30 × 200 – 4.8).
Applications and users
ISO 4018:2022 is intended for:
- Fastener manufacturers and quality control teams specifying production tolerances and head geometry.
- Procurement and engineering teams writing specifications for screws in machinery, structural assemblies, automotive and general industrial applications.
- Distributors and supply-chain managers ensuring correct labelling, traceability and lot control.
- Inspectors and testing laboratories performing acceptance inspection and conformity assessment.
Practical benefits include harmonized dimensions, improved interchangeability, clear labelling requirements for traceability, and consistent reference to coatings and mechanical properties.
Related standards
Key referenced standards to use alongside ISO 4018:2022:
Keywords: ISO 4018:2022, hexagon head screws, product grade C, metric coarse pitch threads, M5–M64, fasteners, screw dimensions, fastener tolerances.
