ISO/TR 20172:2021

Overview

ISO/TR 20172:2021 - Welding - Grouping systems for materials - European materials provides a European-specific grouping system for materials used in welding and allied processes. The technical report classifies standardized European steels, aluminium and its alloys, copper and its alloys, cast irons, and nickel and nickel alloys in accordance with the international grouping system of ISO/TR 15608. It is also applicable for related activities such as heat treatment, forming and non-destructive testing (NDT).

Key topics

• Material grouping for welding: Tables list European designations mapped to the ISO/TR 15608 grouping system (Tables 1–6 in the document), enabling consistent classification across projects and specifications.
• Covered material families: steel, aluminium alloys, copper alloys, cast irons, and nickel and nickel alloys.
• Scope limits and informative classification: the report notes that some listed materials may have chemical composition or mechanical properties outside ISO/TR 15608 limits; such classifications are informational and welding behaviour can differ - welding conditions should be specifically adapted.
• No normative references: the report is a technical guidance document (TR) and does not contain normative references or new definitions; it relies on established ISO/CEN material standards and EN designations.
• Revision highlights: the 2021 (third) edition updates Tables 1–5 and adds a new table for nickel and nickel alloys (Table 6).

Practical applications

• Welding procedure specification (WPS) development: use material groupings to determine prequalified parent metal groups and to select compatible filler metals and welding parameters.
• Welding qualification and testing: helps classify base materials for weld procedure and welder qualification per common grouping rules.
• Material selection and procurement: procurement teams and engineers can reference grouped designations when specifying materials for welded fabrications.
• Heat treatment, forming, and NDT planning: material grouping informs post-weld heat treatment limits, forming considerations and appropriate NDT approaches.
• Standards alignment: supports interoperability between ISO and European (EN) material specifications.

Who should use this standard

• Welding engineers, fabricators and welding coordinators
• Materials engineers and metallurgists
• Quality assurance / inspection teams and NDT specialists
• Procurement and specification writers
• Standards committees and certification bodies

Related standards

• ISO/TR 15608 - International grouping system for materials for welding (primary classification basis)
• ISO/TR 20173 and ISO/TR 20174 - Applicable when materials are not listed in ISO/TR 20172
• Relevant EN material standards referenced in the tables (e.g., EN 10028, EN 10216 series).

Keywords: ISO/TR 20172:2021, welding grouping systems, European materials, material classification for welding, steel aluminium copper nickel cast iron, ISO/TR 15608, welding qualification, heat treatment, NDT.