ISO 4032:2023

Overview - ISO 4032:2023 (Hexagon regular nuts, style 1)

ISO 4032:2023 specifies the dimensional and product requirements for hexagon regular nuts (style 1) made in steel and stainless steel, with metric coarse-pitch threads M5 to M39, delivered in product grades A and B. The fifth edition (2023) updates sizes, tolerances and references to mechanical property standards. It also adds marking and labelling requirements and places non‑conforming historical sizes (D < M5 and D > M39) in an informative Annex A.

Key topics and technical requirements

• Scope & sizes: Nuts covered for thread sizes M5–M39; historical nuts outside this range are retained in Annex A for reference but are not recommended for new or critical use.
• Dimensions & tolerances: Detailed dimensional tables and figures (for nuts with and without washer-face) specify parameters such as height (m), width across flats (s), bearing face (d), and tolerances with numeric precision.
• Threading: Thread tolerance class 6H and coarse-pitch metric threads per ISO 965-1.
• Materials & mechanical properties:
  • Steel nuts: property classes referenced to ISO 898-2 (including quenching/tempering requirements where applicable).
  • Stainless steel nuts: grades and property classes referenced to ISO 3506-2 (A2, A4, D4, D6 examples included).
• Product grades: Grade A for smaller sizes (generally ≤ M16) and B for larger sizes (> M16); product-grade specific dimensional limits are defined in Tables 1 and 2.
• Surface condition & coatings: As‑processed, electroplated or non‑electrolytically applied coatings per ISO 4042 / ISO 10683 / ISO 10684; coating selection can affect thread tolerance position.
• Quality & inspection: Acceptance inspection per ISO 3269; surface discontinuities and integrity per ISO 6157-2.
• Marking & labelling: On-product marking follows ISO 898-2 or ISO 3506-2; package labelling must include reference to ISO 4032, thread size, property class/grade, finish, manufacturer ID, lot number and quantity.

Applications - who uses ISO 4032

• Fastener manufacturers and toolmakers for production and QA of hexagon nuts.
• Design and mechanical engineers specifying nuts for machinery, automotive, construction and industrial equipment.
• Procurement and quality inspectors ensuring purchased nuts meet dimensional, mechanical and marking requirements.
• Standards compliance teams implementing traceability, labelling and acceptance inspection.

Practical benefits: consistent interchangeability, predictable mechanical behavior when matched with ISO‑specified bolts, and clearer procurement/traceability via standardized designation (e.g., "Hexagon regular nut ISO 4032 – M12 – 8").

Related standards

Key cross-references include: ISO 898-2, ISO 3506-2, ISO 965-1, ISO 4759-1, ISO 4042, ISO 10683, ISO 10684, ISO 3269, ISO 8991, ISO 8992. These govern mechanical properties, thread tolerances, coatings, tolerances and designation systems.

Keywords: ISO 4032, hexagon regular nut, style 1, metric nuts, M5–M39, nut dimensions, ISO fastener standards, property class, stainless steel nuts, nut tolerances.