Fatigue life prediction of load carrying cruciform joints of pressure vessel steel by statistical tools

Mathematical models have been developed to predict the fatigue life of shielded metal arc welded (SMAW) and flux cored arc welded (FCAW) cruciform joints failing from root and toe regions. High strength, quenched and tempered steel (ASTM 517 `Fʹ grade) has been used as the base material throughout the investigation. The design of experiments (DoE) concept has been used to optimize the required number of fatigue testing experiments. Fatigue experiments have been conducted in a mechanical resonance pulsator, under constant amplitude loading. The models have been developed by use of the Regression Analysis. The Analysis of Variance (ANOVA) method has been applied to find the significant factors. The adequacy of the developed models has been checked by calculating the correlation coefficient. By using the developed models, the fatigue life of SMAW and FCAW cruciform joints can be predicted at 95% confidence level.