ISO 5817:2023

Overview - ISO 5817:2023 (Welding quality levels)

ISO 5817:2023 - “Welding - Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) - Quality levels for imperfections” defines weld acceptance criteria for fusion-welded joints (excluding beam welding) in a wide range of materials. Applicable to material thickness ≥ 0.5 mm, the standard provides three quality levels (B, C, D) to suit differing design, service and economic requirements. It is a production-oriented reference for assessing typical weld imperfections and supports consistent weld inspection and fabrication quality control.

Key topics and technical requirements

• Quality levels B, C and D: three graded acceptance levels where B denotes the most stringent finish and D the least; selection should be made before production.
• Scope of joints and processes: covers fully penetrated butt welds, fillet welds and can be applied to partial-penetration butt welds; applies to manual, mechanized and automatic welding in all positions. Welding processes included (per ISO 4063) are, for example, metal arc, submerged arc, gas-shielded arc, tungsten inert gas, plasma and (for steel) oxyfuel.
• Types of imperfections: Table 1 of the standard lists dimensional limits and acceptability criteria for common imperfections - e.g., pores, crater cracks, lack of fusion, undercut and shrinkage grooves - referenced to ISO 6520-1 designations.
• Inspection emphasis: directly applicable to visual testing; values for imperfections are given in actual dimensions and may require NDT for detection or sizing. ISO 17635 is referenced for correlating quality levels with NDT methods.
• Fatigue considerations: Annex B offers additional guidance where fatigue performance is a design driver.
• Exclusions and limits: beam welding is excluded (see ISO 13919-1 for beam-welded joints); metallurgical properties (grain size, hardness) are not covered.

Practical applications - who uses ISO 5817:2023

ISO 5817:2023 is used by:

• Welding engineers and designers to specify weld acceptance criteria and select appropriate quality levels for components.
• Fabricators and welding contractors to set production standards and workmanship targets.
• Quality managers and inspectors for visual assessment and to plan NDT activities.
• Procurement and contract writers to include clear weld-quality requirements in orders and specifications.
• Certification bodies and compliance auditors evaluating welded fabrication.

Use cases include pressure equipment, structural fabrication, piping, marine and industrial assemblies where consistent, documented weld quality levels and acceptance criteria are required.

Related standards

• ISO 13919-1 - beam-welded joint quality levels (steel)
• ISO 6520-1 - classification of weld imperfections
• ISO 4063 - welding process identification
• ISO 17635 - NDT correlation and guidance for welds
• ISO 25901 series, ISO/TR 25901-1 and ISO 8501-3 - related terminology and surface preparation guidance

ISO 5817:2023 is a practical, production-focused standard for managing and specifying weld quality, helping stakeholders balance safety, performance and cost in welded fabrication.