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.