ISO 20378:2017

Overview

ISO 20378:2017 - Welding consumables - Rods for gas welding of non‑alloy and creep‑resisting steels - Classification specifies a classification system for rods used in gas (oxy‑fuel) welding based on the chemical composition of the rod. The standard defines product/ process symbols, composition symbols, testing and rounding rules, retest procedures, and designation examples to ensure consistent identification and traceability of gas welding rods for non‑alloy and creep‑resisting steels.

Key topics and requirements

• Scope and purpose: Classification of gas welding rods (oxy‑fuel) for non‑alloy and creep‑resisting steels according to rod chemical composition.
• Product/procedure symbol: The letter O identifies rods intended for oxy‑fuel (gas) welding.
• Composition symbols: Table 1 assigns symbols (I to VI and numeric groups such as 45, 60, 65, 100, Z) to defined ranges of elements (C, Si, Mn, P, S, Mo, Ni, Cr, Cu, Al, V). A Z prefix is used for other agreed compositions.
• Chemical analysis: Analyses are performed on rod samples by any analytical technique; in disputes, recognized published methods should be used.
• Rounding and units: Measured values must be rounded per ISO 80000‑1 rules; averages are rounded after calculation.
• Retest procedure: If tests fail, two repeat tests are required; failing repeats mean the material does not meet classification.
• Delivery requirements: Technical delivery conditions reference ISO 544 for marking, dimensions and tolerances.
• Designation example: ISO 20378 – O III (standard number + oxy‑fuel symbol + composition symbol).
• Welding behavior: Annex A gives informative guidance on typical welding behavior (fluidity, spatter, porosity sensitivity) for symbols I–VI.

Applications

ISO 20378:2017 is practical for:

• Manufacturers and suppliers of welding consumables for consistent product labeling and specification of gas welding rods.
• Welding engineers and fabricators selecting appropriate rods for non‑alloy or creep‑resisting steels based on chemical compatibility and expected weld behavior.
• Quality control and testing laboratories performing chemical analyses and certification of welding rods against defined composition classes.
• Procurement and inspection teams requiring standardized product designations for contracts, goods receipt and conformity assessment.
• Standards writers and regulatory authorities referencing a harmonized classification for gas welding consumables.

Related standards

• ISO 544 (delivery conditions for welding consumables)
• ISO 80000‑1 (rounding and units)
• EN 12536, AWS A5.2/A5M (historical/related classification documents)
• Referenced test methods (e.g., ASTM E350) for chemical analysis

Keywords: ISO 20378:2017, welding consumables, rods for gas welding, oxy‑fuel, gas welding rods, classification, chemical composition, non‑alloy steels, creep‑resisting steels, welding rod designation.