This International Standard provides quality levels of imperfections in fusion-welded joints (except for beam welding) in all types of steel, nickel, titanium and their alloys. It applies to material thickness above 0,5 mm. Three quality levels are given in order to permit application to a wide range of welded fabrication. They are designated by symbols B, C and D. The quality levels refer to production quality and not to the fitness-for- purpose of the product manufactured.