SIST EN ISO 4033:2023 PDF

Overview - EN ISO 4033:2023 (Hexagon high nuts, style 2)

EN ISO 4033:2023 / ISO 4033:2023 defines the characteristics, dimensions and delivery requirements for hexagon high nuts (style 2) made of steel and stainless steel, covering metric coarse pitch threads M5 to M39 and product grades A and B. The standard specifies dimensional tables, tolerance and thread class guidance, marking and labelling, and references for mechanical and surface requirements. Unless otherwise ordered, nuts are supplied without the optional washer-face.

Key topics and technical requirements

• Scope & sizes: Metric coarse pitch threads from M5 to M39; product grade A for D ≤ M16 (special provision for M5) and B for larger sizes.
• Dimensions & tolerances: Detailed dimensions (height, across-flats, across-corners, washer-face options) are given in tables for product grades A and B; thread tolerance position typically 6H.
• Materials & property classes: Steel nuts and stainless steel nuts are covered. Property classes and stainless grades are selected from ISO 898-2 (carbon/alloy steel) and ISO 3506-2 (corrosion‑resistant stainless steel) when required.
• Mechanical & heat treatment: Requirements reference ISO 898-2 for mechanical properties; some steel nuts may be quenched and tempered per ISO 898-2.
• Surface condition & coatings: Default delivery is “as processed” for steel and “clean and bright” for stainless steel. Coatings and finishes (electroplating, zinc flake, hot-dip galvanizing) are referenced to ISO 4042, ISO 10683 and ISO 10684; any special finish to be agreed at order.
• Marking & labelling: Product marking follows ISO 898-2 (steel) or ISO 3506-2 (stainless); package labelling must include ISO 4033 reference, thread size, property class/grade, finish, manufacturer, lot number and quantity.
• Inspection & acceptance: Acceptance inspection per ISO 3269; surface discontinuities per ISO 6157-2.

Practical applications and who uses it

This standard is essential for:

• Fastener manufacturers (production, quality control)
• Design and mechanical engineers specifying nuts for machinery, structural assemblies, automotive and industrial equipment
• Procurement and specification writers preparing purchase orders and ensuring compliance
• Quality inspectors and testing labs performing acceptance and dimensional checks

Use EN ISO 4033:2023 to ensure interchangeability, correct mechanical performance, consistent marking and traceability of hexagon high nuts across supply chains.

Related standards (for specification and compliance)

• ISO 898-2 - Mechanical properties (steel nuts)
• ISO 3506-2 - Stainless steel fasteners (nuts)
• ISO 965-1 - Metric thread tolerances
• ISO 4759-1 - Tolerances for fasteners (product grades)
• ISO 3269 - Acceptance inspection
• ISO 4042 / 10683 / 10684 - Coating systems and finishes

Keywords: EN ISO 4033:2023, ISO 4033, hexagon high nuts, fasteners, metric M5–M39, product grade A B, ISO 898-2, ISO 3506-2, marking and labelling.