ON RELATION BETWEEN FATIGUE PROPERTIES OF WELDED JOINTS, QUALITY CRITERIA AND GROUPS IN ISO 5817

The worldwide accepted standard for ensuring weld quality is ISO 5817. This standard developed from an old German standard, DIN 8563, which was originally intended as a means for understanding between welders in a workshop and the inspectors performing optical and non-destructive control of the welded joint. The criteria and groups were predominantly established in consideration of the effort to produce or to inspect a weld. Neither static nor fatigue strength of the welded joint were considered. Since that time research has progressed so that service behaviour can be assessed based on knowledge of the existing weld imperfections. This paper includes tables which correlate the fatigue strength of a joint with the quality criteria and groups of ISO 5817. The correlation has been established using butt and fillet welded joints in 10 mm thick plates as an example. The German Welding Society (DVS) has updated its guidance on the application of ISO 5817. Fatigue strength is one consideration in this effort. A revised version of ISO 5817 is under development. The present paper supports these activities by describing the current state of the art in terms of the relationship between weld quality criteria and groups with fatigue strength. It provides a realistic basis on which to define consistent quality levels in relation to fatigue strength. Thus, an economic specification of quality levels is made possible.