Residual Stresses at Girth-Butt Welds in Pipes and Pressure Vessels.

摘要

The objective of the research program is to develop mathematical models for calculating the magnitude,direction,and distribution of residual stresses at girth-butt welds. The program is divided into three tasks. Task 1focuses on a critical review of current literature and available reports to obtain data and analytical techniques for predicting temperature distributions and residual stresses in girth-butt welds. Task 2involves experimental evaluation of residual stresses for girth-butt welds to provide guidance for development of the analytical models. Task 3is the development of analytical methods for predicting residual stresses. Two distinct mathematical models are needed. First,since residual stresses at butt welds are thermally induced, a model to represent the transient temperature distribution for each weld pass is needed. Secondly, a stress analysis model that treats the temperature distribution as input and predicts stresses as a function of weld-pass geometry,material properties,and the geometry of the pipe is needed.