This Technical Reportprovides a uniform system for the grouping of materials for welding purposes. It can also apply to other purposes@ such as heat treatment@ forming and non-destructive testing. This Technical Report covers 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