This part of ISO 6520 will serve as the basis for a precise classification and description of weld imperfections. In order to avoid any confusion, the types of imperfection are defined with explanations abd illustrations where necessary. Mettalurgical imperfections are not included. NOTE: In addition terms and definitions used in two of the three official ISO languages (English and French), this part of ISO 6520 gives the equivalent terms and definitions in the German language; these are published under the responsability of the member body for Germany (DIN). However, only the terms and definitions given in the official languages can be considered as ISO terms and definitions.