Overview
ISO 6362-4:2022 - "Wrought aluminium and aluminium alloys - Extruded rods/bars, tubes and profiles - Part 4: Tolerances on form and dimensions for profiles" - defines the permissible dimensions and geometric form tolerances for extruded aluminium profiles whose cross-section fits within a circumscribing circle up to 800 mm. It applies to extruded profiles for general engineering applications and complements other parts of the ISO 6362 series (notably ISO 6362-1 and ISO 6362-7).
Key topics and technical requirements
- Scope limits: Profiles with a circumscribing circle ≤ 800 mm; general engineering use only.
- Dimensional tolerances: Tables (ordinary and special classes) provide tolerances by nominal section sizes, alloy group and feature type. Tolerance values vary with:
- cross‑section size (A, D etc.),
- whether the profile is solid or hollow,
- alloy group (Group I and Group II as listed in ISO 6362-7),
- and the local geometry (e.g., thin walls, openings).
- Tolerances on form: Requirements and definitions for:
- Straightness
- Convexity / concavity
- Curved cross-section or contour
- Twist
- Angularity
- Corner and fillet radii
- Length and end conditions: Rules for acceptable lengths and squareness of cut ends.
- Special cases & purchaser-supplier agreement:
- When wall-thickness ratios, hollow-space percentages or angled features occur, tolerances can require mutual agreement.
- Purchaser must specify whether ordinary or special tolerances are required and whether outside or inside dimensions are to be controlled.
Practical applications - who uses ISO 6362-4
- Extrusion mills and manufacturers - to set production tolerances and quality targets for extruded aluminium profiles.
- Design and mechanical engineers - to specify realistic tolerances during product design and ensure interchangeability.
- Purchasers and procurement teams - to define inspection and delivery conditions in contracts (ordinary vs special class).
- Quality managers and inspection labs - to verify conformity against the standard’s tolerance tables and form criteria.
- Fabricators and assemblers - to anticipate fit, function and machining allowances when using extruded profiles.
Related standards and references
- ISO 6362 series - other parts cover inspection/delivery (ISO 6362-1) and alloy listings (ISO 6362-7).
- The standard references the ISO/IEC Directives for development and maintenance.
Keywords: ISO 6362-4, aluminium extruded profiles tolerances, tolerances on form and dimensions, wrought aluminium, extrusion tolerances, aluminium alloys, profile tolerances.