ISO 2107:2023

Overview - ISO 2107:2023 (Aluminium temper designations)

ISO 2107:2023 specifies the temper designations used to identify the condition of wrought aluminium and aluminium alloys. The fourth edition (2023) defines the system of letters and digits (for example F, O, H, W, T and their numeric subdivisions) that follow an alloy designation (separated by a hyphen) to indicate the metallurgical and mechanical condition produced by mechanical and/or thermal processing. The document applies to all product forms of wrought aluminium and aluminium alloys and provides rules for consistent product identification and communication across the supply chain.

Key topics and technical requirements

• Scope and terminology: Clear definitions of temper, annealing, strain-hardening, solution heat-treatment, ageing and stress-relieving are included to ensure consistent interpretation.
• Basic temper designations:
  • F - as fabricated (no special thermal/strain control).
  • O - annealed (lowest strength, with numeric subdivisions for special anneals such as O1 and O3).
  • H - strain-hardened (always followed by at least two digits indicating operation sequence and degree of hardening).
  • W - solution heat-treated (unstable temper; natural ageing periods may be specified).
  • T - precipitation hardened (stable tempers, with numeric sequences describing treatments).
• Numeric subdivisions: Digits after H and T denote specific sequences (e.g., H21–H29 series, T351 types), degree of strain hardening, partial or full anneals, stabilization treatments, and variations that affect mechanical or physical properties.
• Identification practice: Temper designation follows the alloy name, and additional digits are used when variations produce different characteristics. Annex A documents common regional temper designations.
• Editorial updates: This edition adds Clause 2, updates terms in Clause 3, revises Clause 4, and adds Annex A for regional usage.

Practical applications and users

ISO 2107:2023 is used by:

• Manufacturers and mill producers for labeling and declaring temper on product certificates.
• Design and mechanical engineers specifying material conditions for component performance (strength, ductility, machinability).
• Quality and inspection teams verifying that delivered product tempers match purchase specifications.
• Purchasing and procurement to unambiguously request required tempers in contracts and drawings.
• Standards writers and regulatory bodies aligning product identification across national and regional specifications.

Related guidance

• Prepared by ISO/TC 79 (Light metals and their alloys, Subcommittee SC 9 - Symbolization).
• Annex A - provides common, regionally applied temper designations and descriptions.
• For property limits and alloy-specific requirements, consult the relevant product or alloy standards that specify mechanical and physical limits for alloy–temper–product combinations.

Keywords: ISO 2107:2023, aluminium temper designations, wrought aluminium, H temper, T temper, O temper, F temper, W temper, strain-hardening, solution heat-treated, precipitation hardened, temper identification.