Statistical Analysis of Fatigue Data From an Interlaboratory Testing Program on Weld Improvement Techniques

A fatigue testing program has been designed to determine the effect on the fatigue strength of several post weld improvement techniques. The program was organized by Commission XIII of the International Institute of Welding (IIW) and twelve testing laboratories in nine countries participated. The main objective of the round-robin test program was to check the reproducibility of the treatments, and secondly to establish design guidance in terms of level of improvement in fatigue strength. Twelve large welded steel plates were distributed and the treatments that included burr grinding, TIG dressing and three types of peening were performed on plate segments in each laboratory. Simple T-joint specimens were fabricated and fatigue testing was carried out following a prescribed procedure. Standard regression analysis was made and the results were reported by each laboratory. The paper briefly reviews the test program and the statistical analyses that were used to evaluate the results.