Overview
EN ISO 15608:2025 - Welding - Grouping system for metallic materials (ISO 15608:2025) specifies a uniform, international system for grouping metallic materials for welding purposes. The standard covers steels, aluminium and its alloys, copper and copper alloys, nickel and nickel alloys, titanium and titanium alloys, zirconium and zirconium alloys, cast irons and cobalt alloys. Although focused on welding, the grouping system can also be applied to heat treatment, forming and non‑destructive testing (NDT) and supports consistent material classification across design, fabrication and inspection activities.
Key topics and technical requirements
- Material coverage and grouping codes: Defines group ranges for each material family (e.g. steels groups 1–11; aluminium groups 21–26; copper groups 31–38; nickel groups 41–48; titanium groups 51–54; zirconium groups 61–62; cast irons groups 71–76).
- Grouping criteria: Uses chemical composition (elemental limits used in alloy designations) and mechanical properties (specified minimum yield strength) to assign materials to groups.
- Analysis precedence: Recommends using ladle (heat) analyses in preference to product analyses when both are specified. Only elements specified in the material standard or specification shall be considered.
- Thickness and strength considerations: When minimum yield strength varies with thickness, the highest specified strength is used to determine the subgroup.
- Interoperability with existing guidance: Materials assigned in ISO/TR 20172, ISO/TR 20173 and ISO/TR 20174 are considered assigned to the corresponding groups in this standard.
- Standard status: This first edition converts the previous ISO/TR 15608:2017 into an International Standard and updates the title and format.
Practical applications and users
EN ISO 15608:2025 is intended for professionals who need a consistent material‑grouping baseline in welding and allied operations:
- Welding engineers and procedure writers - for selecting appropriate filler metals and qualifying welding procedures (WPS/PQR).
- Fabricators and manufacturing engineers - to classify incoming materials for weldability, heat treatment and forming.
- Quality managers and inspectors - to harmonize NDT acceptance criteria and inspection planning across material groups.
- Material suppliers, designers and procurement teams - to specify group-compatible materials and reduce ambiguity in purchase orders.
- Certification bodies and standards committees - to reference a uniform grouping system in regulations and industry codes.
Related standards
Using EN ISO 15608:2025 helps organizations standardize material classification for welding, simplify procedure qualification decisions, and improve consistency between design, fabrication and inspection workflows.
