ISO 636:2024

Overview

ISO 636:2024 - "Welding consumables - Rods, wires and deposits for tungsten inert gas (TIG) welding of non-alloy and fine‑grain steels - Classification" - is the sixth edition of the ISO classification for TIG welding filler materials. It specifies how to classify rods, wires and weld deposits for TIG welding of non‑alloy and fine‑grain steels with a minimum yield strength up to 500 MPa or a minimum tensile strength up to 570 MPa. The standard provides a combined classification system based on mechanical properties of the all‑weld metal and the chemical composition of the consumable.

Key topics and technical requirements

• Two classification systems
  • System A - classification by yield strength and average Charpy impact energy 47 J (all‑weld metal).
  • System B - classification by tensile strength and average Charpy impact energy 27 J (all‑weld metal).
• Designation rules
  • Symbols begin with the letter “W” for tungsten inert gas welding.
  • Suffix “system A” or “system B” indicate which approach applies; absence of a suffix means the designation is applicable to both systems.
• Impact test protocols
  • System A: three Charpy specimens, average ≥ 47 J; one value may be lower but not below 32 J.
  • System B: five specimens, discard highest and lowest, average of remaining three ≥ 27 J; one of the three may be below 27 J but not below 20 J.
• Mechanical testing and conditions
  • All‑weld metal test-piece preparation, preheating/interpass and post‑weld heat treatment (PWHT) conditions are specified (see Clause 6).
• Chemical composition
  • Rods and wires are classified by chemical composition (Table 4); deposits follow the chemical composition of the consumable plus the mechanical properties of the all‑weld metal (Tables 2–4).
• Conformity and delivery
  • Includes rounding procedures, retesting rules, and technical delivery conditions (Clause 10).
• Updates in 2024 edition
  • Reformatting, updated references, revised mechanical/chemical requirements, new system B classifications and clarifications on preheat/interpass and boron footnote.

Applications and users

ISO 636:2024 is practical for:

• Welding engineers and metallurgists selecting TIG welding consumables for non‑alloy and fine‑grain steels.
• Manufacturers of welding rods and wires seeking compliant product classification.
• Fabricators, inspectors and procurement teams specifying filler materials to match strength and impact requirements of parent material.
• Quality management and certification bodies verifying mechanical test results and documentation.

Practical benefits include clearer consumable selection, consistent all‑weld metal performance expectations, and harmonized procurement language for TIG welding projects.

Related standards

• ISO 15792‑1 (all‑weld metal test piece preparation)
• ISO 14175 (welding gases)
• ISO 544, ISO 14344 (technical delivery / procurement of filler materials)
• EN 1668 (informative for system A references)

Keywords: ISO 636:2024, welding consumables, TIG welding, tungsten inert gas, rods, wires, all‑weld metal, classification, yield strength, tensile strength, impact energy, non‑alloy steels.