This document specifies a uniform system for grouping materials for welding purposes. This document can also be applied for other purposes, such as heat treatment, forming and non-destructive testing. This document is applicable to grouping systems for the following standardized materials: — steels; — aluminium and its alloys; — copper and its alloys; — nickel and its alloys; — titanium and its alloys; — zirconium and its alloys; — cast irons; — cobalt alloys.