SIST EN 1780-1:2004

Overview

EN 1780-1:2002 (CEN) defines a standardized five-figure numerical designation system for alloyed aluminium ingots for remelting, master alloys and castings. The standard applies to products for all applications, including aerospace, and is part of a three‑part EN family that also covers a chemical‑symbol designation (EN 1780-2) and writing rules for chemical composition (EN 1780-3). Unalloyed aluminium is covered separately (EN 576).

Key Topics and Requirements

• Designation format: The designation starts with the prefix EN, then A (aluminium), a letter for product form (B = alloyed ingots for remelting, C = castings, M = master alloys), a hyphen, then five figures (e.g., EN AB-44000, EN AM-91400).
• First digit – major alloying element:
  • 2XXXX = copper-based alloys
  • 4XXXX = silicon-based alloys
  • 5XXXX = magnesium-based alloys
  • 7XXXX = zinc-based alloys
• Second digit – alloy group: identifies subgroups (examples include 21XXX = Al–Cu, 41XXX = Al–SiMgTi, 42XXX = Al–Si7Mg, 43XXX = Al–Si10Mg, 44XXX = Al–Si, 45XXX = Al–Si5Cu, 46XXX = Al–Si9Cu, 47XXX = Al–Si(Cu), 48XXX = Al–SiCuNiMg, 51XXX = Al–Mg, 71XXX = Al–ZnMg).
• Third digit: arbitrary (used for further subgrouping).
• Fourth digit: generally 0.
• Fifth digit: normally 0; exceptions apply for aerospace designations (see EN 2032‑1 for aerospace prefix rules).
• Master alloys coding: begin with 9 as the first digit; the second and third digits correspond to the atomic number of the main alloying element (examples: 105 for boron, 214 for silicon, 329 for copper). The last two digits are chronological; even = low impurity grade, odd = high impurity grade.

Applications and Who Uses It

• Foundries and remelters use EN 1780-1 to label and identify alloy ingots and castings consistently.
• Master alloy producers apply the master-alloy numbering rules to communicate composition and impurity class.
• Purchasing/specification teams rely on the numerical system for procurement and material traceability.
• Aerospace and transport manufacturers use the standard (in conjunction with EN 2032‑1) for part material identification and regulatory compliance.
• Quality assurance and certification bodies reference the designation rules for conformity and documentation.

Related Standards

• EN 1780-2 - Chemical symbol based designation system (alternative system).
• EN 1780-3 - Writing rules for chemical composition.
• EN 576 - Unalloyed aluminium ingots for remelting.
• EN 2032-1 - Aerospace series: conventional designation (prefix rules for aerospace alloys).

This standard promotes uniform alloy identification across the aluminium supply chain, improving material specification, procurement clarity, and interoperability in industrial and aerospace applications.