ISO 10042:2005 specifies quality levels for imperfections in arc-welded joints in aluminium and its alloys. It applies to material thicknesses above 0,5 mm. It covers full-penetration butt welds and all fillet welds. The principles of the standard may also be applied to partial-penetration butt welds. Three quality levels are given in order to permit application to a wide range of welded constructions. The quality levels refer to production quality and not to the fitness for purpose of the product manufactured. The standard applies to: all types of weld, e.g. butt welds, fillet welds and branch connections; the following welding processes and their sub-processes as defined in ISO 4063: 131....metal inert gas welding (MIG welding); gas metal arc welding /USA/, 141....tungsten inert gas welding (TIG welding); gas tungsten arc welding /USA/, 15......plasma arc welding; manual, mechanized and automatic welding; all welding positions. Metallurgical aspects, e.g. grain size, hardness, are not covered by the standard.