EN ISO 6520-1:1998 Welding and Allied Processess - Classification of Geometric Imperfections in Metallic Materials - Part 1: Fusion Welding ISO 6520-1:1998; Supersedes EN 26520:1991
2007EN ISO 6520-1:2007 Welding and allied processes - Classification of geometric imperfections in metallic materials - Part 1: Fusion welding (ISO 6520-1:2007)
1998EN ISO 6520-1:1998 Welding and Allied Processess - Classification of Geometric Imperfections in Metallic Materials - Part 1: Fusion Welding ISO 6520-1:1998; Supersedes EN 26520:1991