ISO 9692-3:2016

Overview

ISO 9692-3:2016 - "Welding and allied processes - Types of joint preparation - Part 3" provides recommended joint preparation types and design limits for MIG (131) and TIG (141, 142) welding of aluminium and its alloys. The standard covers recommended joint geometries, angles, gaps and root-face details for fully penetrated welds, and is intended to guide designers, fabricators and welding engineers in selecting suitable joint preparations for aluminium welding.

Key topics and technical requirements

• Scope and materials: Suitable for all weldable aluminium alloys; applies to fully penetrated welds.
• Welding processes covered:
  • Metal Inert Gas (MIG) welding with solid wire (ISO 4063 ref. 131)
  • Tungsten Inert Gas (TIG) welding with filler (141)
  • Autogenous TIG (142) - limited application (butt welds between plates with raised edges)
• Joint types and dimensions: Recommended joint preparations and dimensional ranges are given in Tables 1–3 for:
  • Butt welds welded from one side (Table 1)
  • Butt welds welded from both sides (Table 2)
  • T‑joints and fillet welds (Table 3)
• Design parameter guidance:
  • Angles, gaps and root-face thickness ranges are specified as design limits, not manufacturing tolerances.
  • The choice of angle/gap depends on plate thickness, welding position and process; larger gaps (≥ 1.5 mm) allow smaller bevel angles and backing is preferred when gaps ≥ 1.5 mm.
  • For single-sided welding, grooved backing bars are recommended; backing may be temporary (MR) or permanent (M).
• Preparation and finish:
  • Edges should be prepared mechanically (shearing, sawing, milling).
  • Do not use mineral oil–based cleaning fluids.
  • If plasma cutting is used, check cut quality (e.g., cracks).
  • Root faces and longitudinal edges should be de-burred and chamfered, especially for single-sided butt welds without backing.
• Normative references: ISO 2553 (welding symbols) and ISO 4063 (process nomenclature).

Practical applications and users

This standard is practical for:

• Welding engineers and designers specifying joint geometry for aluminium structures
• Fabricators and shop supervisors preparing weld-ready parts
• Welding procedure writers and quality inspectors validating joint details
• Technical standard committees and educators referencing consistent joint-prep practice

Typical applications include pressure-containing assemblies, aluminium frames, extruded profiles and general structural welding where fully penetrated MIG/TIG welds are required.

Related standards

• ISO 9692 (other parts): Part 1 (steels), Part 2 (submerged arc), Part 4 (clad steels)
• ISO 2553:2013 - Symbolic representation on drawings
• ISO 4063 - Nomenclature of welding processes

Keywords: ISO 9692-3:2016, joint preparation, aluminium welding, MIG, TIG, butt weld, T-joint, backing, root face, welding design.