Overview
ISO 7380-1:2022 - Fasteners - Button head screws with reduced loadability - Part 1: Hexagon socket button head screws - specifies the dimensional, mechanical and marking requirements for hexagon socket button head screws with reduced loadability in steel and stainless steel. The standard covers metric coarse pitch threads M3 to M16, product grade A, and defines how reduced loadability (due to head geometry and socket penetration) limits ultimate tensile load and how this is indicated in marking.
Key Topics and Technical Requirements
- Scope and materials: Applies to steel and stainless-steel screws. Stainless steel grades may be selected from ISO 3506-1 when other specifications are requested.
- Reduced loadability definition: Head design combined with hexagon socket penetration reduces head load capacity; the loadability in the head is assumed to be 80% of that in the thread. This reduction is shown by a specific property-class marking preceded by a zero (e.g., 08.8 → 08.8 with leading zero symbol convention for reduced loadability).
- Dimensions and tolerances: Detailed head, socket and thread dimensions (including socket depth t, wall thickness w, reference datum for head diameter d_ref and underhead radii) are given for M3–M16. Broached socket guidance and maximum overcut (≤ 1/3 of socket-flat length) are included.
- Mechanical requirements: Minimum ultimate tensile loads for reduced-load screws are specified (calculated as 80% of full-load values). Reference mechanical standards include ISO 898-1 for steel and ISO 3506-1 for stainless steel.
- Thread and product grades: Threads per ISO 965-1, tolerance class 6g; product grade A; surface and coating options referenced to ISO 4042 and ISO 10683.
- Marking and labelling: Product and package labelling requirements (including reference to ISO 7380-1, thread size, length, property class or stainless grade, finish, lot number and quantity) are specified.
Practical Applications and Users
- Who uses this standard: Fastener manufacturers, mechanical design engineers, procurement specialists, quality and testing laboratories, and OEMs specifying screws for assemblies.
- When to use: Select ISO 7380-1:2022 when a low-profile button head with a hexagon socket is required but where head geometry limits load capacity (e.g., lightweight assemblies, aesthetic fixtures, electronic enclosures, machine panels). Use its dimensional and marking rules to ensure interchangeability, correct tensile performance, and conformity for procurement and inspection.
Related Standards
Keywords: ISO 7380-1:2022, hexagon socket button head screws, reduced loadability, M3–M16, button head screw dimensions, fastener standards, property class, stainless steel fasteners.