ISO 26304:2017

Overview

ISO 26304:2017 - "Welding consumables - Solid wire electrodes, tubular cored electrodes and electrode‑flux combinations for submerged arc welding of high strength steels - Classification" - defines a standardized classification system for submerged arc welding (SAW) consumables used with high‑strength steels (minimum yield strength > 500 MPa or minimum tensile strength > 570 MPa). The standard covers classification of solid wire electrodes, tubular cored electrodes, and electrode‑flux combinations based on mechanical properties of the all‑weld metal in as‑welded and post‑weld heat‑treated conditions.

Key Topics and Requirements

• Two classification systems
  • System A: classification based on yield strength and average impact energy of 47 J.
  • System B: classification based on tensile strength and average impact energy of 27 J.
    Clauses and tables are suffixed “A” or “B” to indicate applicability.
• Symbols and designation: standardized symbols indicate product/process, tensile properties, impact properties, flux type, chemical composition, post‑weld heat treatment, and optional hydrogen content.
• Chemical classification: solid wire electrodes are also classified by chemical composition; tubular wires are classified by the all‑weld metal composition produced with a specific flux.
• Interchangeability rules: one flux may be tested with multiple electrodes and vice versa, but manufacturers’ combinations are not automatically interchangeable without verification.
• Mechanical testing and requirements: tensile and impact tests, preheating/interpass temperature specification, welding conditions and pass sequence for test specimens are specified to ensure repeatable classification results.
• Hydrogen and cracking guidance: optional symbols for diffusible hydrogen (e.g., H2/H4) and an informative annex on potential weld metal hydrogen cracking risks.
• Administrative items: rounding procedures, retests, technical delivery conditions, and examples of designation/marking for procurement and quality control.

Practical Applications - Who Uses ISO 26304:2017

• Welding engineers and metallurgists selecting consumables for SAW on high‑strength steels.
• Consumables manufacturers classifying and marking electrodes, cored wires and electrode‑flux combinations.
• Fabricators and contractors in heavy industries (oil & gas, offshore structures, pressure vessels, pipelines, shipbuilding, heavy machinery) requiring reliable weld metal properties.
• Quality assurance and procurement teams specifying material acceptance criteria and supplier compliance.
• Certification bodies and labs performing tensile, impact and hydrogen tests to verify classification.

Related Standards (normative references)

• ISO 14174 - Flux classification for SAW
• ISO 3690 - Determination of hydrogen in weld metal
• ISO 15792‑1 - Test methods for all‑weld metal specimens
• ISO 544, ISO 6847, ISO 13916, ISO 14344 - delivery, analysis, temperature measurement, procurement guidance

ISO 26304:2017 helps ensure consistent specification, testing and marking of SAW consumables for high‑strength steels, enabling safer, more predictable welding outcomes and clearer procurement and compliance processes.