Overview
EN ISO 20378:2018 (identical to ISO 20378:2017) defines a classification system for welding consumables - rods for gas (oxyfuel) welding of non‑alloy and creep‑resisting steels. The standard specifies how rods are designated based on their chemical composition, the symbol for the gas welding process, and basic delivery and testing principles. It replaces EN 12536:2000 and is intended for manufacturers, test laboratories and users of gas welding rods.
Key topics
- Scope and purpose
- Classification of rods for gas welding in terms of chemical composition.
- Product/process symbol
- The rod symbol for oxyfuel (gas) welding is “O”.
- Chemical composition symbols
- Table 1 in the standard lists symbols (e.g., I, II, III, IV, V, VI and numeric symbols such as 45, 60, 65, 100) linked to specific ranges for elements (C, Si, Mn, P, S, Mo, Ni, Cr, Cu, Al, V, etc.).
- A Z prefix is used for consumables with agreed compositions not listed in the table.
- Chemical analysis and test rules
- Chemical analysis is carried out on rod specimens; any analytical technique may be used, with reference methods applied in disputes.
- Rounding follows ISO 80000‑1 procedures.
- Retesting rules: failed tests are repeated twice; both retests must meet requirements or the batch is non‑conforming.
- Technical delivery and designation
- Delivery conditions reference ISO 544 (dimensions, tolerances, markings).
- Example designation: ISO 20378 - O III (standard – process – chemical symbol).
- Welding behaviour (informative)
- Annex A summarizes typical welding behaviour differences (fluidity, spatter, porosity sensitivity) among symbols I–VI.
Applications
- Selection and specification of appropriate gas welding rods for joining carbon and creep‑resisting steels.
- Quality control and acceptance testing by manufacturers, metal fabrication shops, and independent test laboratories to verify chemical composition and marking.
- Procurement and materials specification in industries using oxyfuel welding (e.g., maintenance welding, structural fabrication, repair work).
- Standardized designation for documentation, traceability and conformity assessment.
Related standards
- ISO 544 - Technical delivery conditions for filler materials and fluxes
- ISO 80000‑1 - Quantities and units (rounding rules)
- EN 12536:2000 (superseded)
- AWS A5.2/A5M, ASTM E350, BS 6200-3 (referenced in bibliography)
Keywords: EN ISO 20378:2018, welding consumables, gas welding rods, non-alloy steels, creep-resisting steels, chemical composition classification, oxyfuel welding.
