Overview
ISO 6847:2020 is an international standard developed by ISO that specifies the procedure for depositing weld metal pads intended for chemical analysis. This standard applies to a comprehensive range of welding consumables including covered electrodes, wire electrodes for gas shielded metal arc welding, tubular cored electrodes, solid and cored rods for gas tungsten arc welding, and wire-flux or strip-flux combinations used in submerged arc welding, electroslag welding, and cladding. It addresses consumables for various metal types such as non-alloy and fine grain steels, high strength steels, creep-resisting steels, stainless and heat-resisting steels, nickel and nickel alloys, as well as copper and copper alloys.
This fourth edition updates and replaces ISO 6847:2013, introducing provisions for flux-strip and flux-wire combinations in welding overlay procedures under flux and electroslag modes, enhancing the versatility and applicability in modern welding practices.
Key Topics
- Scope and Applicability: Defines the welding processes and consumable types for which the chemical analysis procedure is applicable, covering various steels, nickel, and copper alloys.
- Base Metal Requirements: Specifies the chemical composition and physical dimensions of the base metal on which the weld pad is deposited, ensuring consistency in sample preparation.
- Welding Positions and Conditions: Mandates welding in a flat position (ISO 6947 standard) with adherence to current types, polarity, and welding parameters recommended by consumable manufacturers.
- Preparation and Deposition Methods: Details multiple acceptable welding sequences (Methods A through H) for pad deposition, including alternating weld directions and cooling procedures between passes to achieve representative chemical analysis samples.
- Consumable Handling: Covers necessary preparation such as baking (drying) of electrodes and flux-cored wires following manufacturer guidelines to ensure quality weld deposit.
- Dimensions and Sampling: Establishes minimum weld pad sizes and sampling layers to obtain accurate chemical composition results, urging removal of surface oxides and rejecting samples including start or crater zones.
- Welding Parameters Documentation: Emphasizes recording welding conditions like current, voltage, and travel speed to maintain traceability and repeatability in sample preparation.
Applications
- Chemical Analysis of Welding Consumables: Ensures precise chemical characterization of weld metal to verify compliance with quality requirements for manufacturing, structural integrity, and safety.
- Quality Control in Welding Processes: Facilitates standardization of test samples for routine verification of consumable composition, which is critical for aerospace, automotive, construction, and energy sectors.
- Research and Development: Supports development of new welding consumables and processes by providing a standardized method for evaluating the weld metal chemical makeup.
- Regulatory Compliance and Certification: Assists manufacturers and welding specialists in meeting international quality standards and certification requirements tied to material performance.
- Cross-Industry Usage: Applicable for consumables and welding procedures used in industries demanding high performance steels and alloys, including petrochemical, power generation, and repair welding operations.
Related Standards
- ISO 6947 – Welding and allied processes – Position of welding: Defines welding positions including the flat position essential for this procedure.
- ISO 14175 – Welding consumables – Gases and gas mixtures for fusion welding and allied processes: Provides guidance on the protective gas types recommended for use with specific consumables addressed in ISO 6847:2020.
- ISO/IEC Directives – Procedures for drafting and updating international standards: Ensures consistent development of ISO standards.
- IIW Recommendations – Developed in collaboration with the International Institute of Welding for standardizing welding test methods.
ISO 6847:2020 serves as a critical resource for welding professionals seeking to produce reliable, reproducible weld metal samples for accurate chemical analysis, supporting product quality and process optimization across a wide range of welded materials and industries.