Overview
ISO 21952:2012 - Welding consumables - Wire electrodes, wires, rods and deposits for gas shielded arc welding of creep-resisting steels - Classification - defines a unified classification system for filler metals used in gas-shielded arc welding (GMAW) and tungsten inert-gas (GTAW) welding of creep-resisting steels. The standard specifies how wire electrodes, wires and rods (and their all‑weld‑metal deposits) are classified by chemical composition and mechanical performance in the as‑welded or post‑weld‑heat‑treated condition. ISO 21952:2012 is the second edition (revising the 2007 edition) and aligns gas designations with ISO 14175.
Key topics and requirements
- Two classification systems:
- System A - classification primarily by chemical composition plus requirements for yield strength and an average impact energy of 47 J for all‑weld metal.
- System B - classification by tensile strength of all‑weld metal (symbolized by codes such as 49, 52, 55, 57, 62, 69, 78 corresponding to 490–780 MPa minimum tensile strength) together with chemical composition.
- Chemical composition: A comprehensive table of compositional symbols for wires/rods defines ranges for C, Si, Mn, Cr, Mo, V, Ni and other alloying elements; classification uses measured compositions per Clause 6.
- Shielding gas notation: When applicable, a gas symbol (per ISO 14175) is prefixed - e.g., I1 (100% Ar), M12/M13/M20/M21 (mixed gases), C1 (CO2), or Z (unspecified).
- Mechanical and test requirements: Specifies welding conditions, preheat/interpass guidance, mechanical testing of all‑weld specimens, chemical analysis, rounding procedures, retest rules, and technical delivery conditions.
- Designation rules: Clear rules for composing product designations (product/process symbol G or W, strength symbol, gas symbol, composition symbol) and examples.
Applications
ISO 21952:2012 is practical for:
- Specifying and selecting welding consumables for high‑temperature/creep‑resisting components (boilers, power plants, petrochemical equipment, pressure vessels).
- Quality assurance, procurement and technical specifications where weld metal tensile or yield properties and impact toughness must be controlled.
- Manufacturers of wire electrodes and rods for classification, marking and certification of filler metals.
- Welding engineers and materials specialists matching filler metal properties to parent metal performance, especially when tensile strength matching is required.
Related standards
- ISO 14175 (gases and gas mixtures for fusion welding)
- ISO 544 (technical delivery conditions for filler materials)
- ISO 14344 (procurement of filler materials)
- ISO 15792-1 (test methods for all‑weld metal specimens)
- ISO 13916 (preheating/interpass measurement guidance)
Keywords: ISO 21952:2012, welding consumables, wire electrodes, gas shielded arc welding, creep‑resisting steels, classification, shielding gas, all‑weld metal, tensile strength, yield strength, ISO 14175.
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