Effect of Initial Weld Quality on the Benefit of Burr Grinding on Fatigue Strength

Abstract

At the present time, European fatigue recommendations of welded joints are established for metallic constructions (Eurocode 3), and are in preparation for mechanical handling-lifting equipment. For this reason, the French Mechanical Handling-Lifting industry asked CETIM to perform a study on two types of welded joints (butt joints and cruciform joints) in 8 mm thick steel to establish design S-N curves for burr ground joints. A particular objective was to investigate what further improvement in fatigue life could be obtained from this technique in welded joints that met previously established weld quality requirements related to improved fatigue performance. Thus, welded specimens were fabricated by some of the companies with the objective of obtaining weld profiles as defined in those quality requirements, inspected and assessed against the admissible defects, and weld toe burr ground in accordance with IIW recommendations. They were then fatigue tested to determine the S-N curve for each type of welded joints. This paper presents the methodology used and the results obtained. These show better S-N curve than those recommended in IIW recommendations for burr ground cruciform joints.