IIW Recommendations In Methods For Improving The Fatigue Strength Of Welded Joints

• Offers specifications for the practical use of each weld toe method, including equipment, weld preparation and operation
• Provides guidance on inspection, quality control and training, as well as assessment of fatigue strength and thickness effects possible with each technique
• This report will enable a more consistent use of these methods and more predictable increases in fatigue strength

The weld toe is a main source of fatigue cracking because of the severity of the stress concentration it produces. Weld toe improvement can improve the fatigue strength of new structures significantly. It can also be used to repair or upgrade existing structures. However, in practice there have been wide variations in the actual improvements in fatigue strength achieved. Based on an extensive testing programme organised by the IIW, this report reviews the main methods for weld toe improvement to increase fatigue strength: burr grinding, TIG dressing and hammer and needle peening. The report offers specifications for the practical use of each method, including equipment, weld preparation and operation. It also offers guidance on inspection, quality control and training as well as assessments of fatigue strength and thickness effects possible with each technique. IIW recommendations on methods for enhancing the fatigue strength of welded joints will allow a more consistent use of these methods and more predictable increases in fatigue strength.