Experimental investigation and modeling on residual stress of welded steel circular tubes

To investigate the residual stress of welded steel circular tubes, an experimental program including 9 different sectional dimensions and different steel strength specimens were described in which sectioning method was employed. Based on large quantities of original test data, the residual stress distribution and the magnitudes of these different specimens were obtained, and the effects of the diameter to thickness ratio, the steel strength and hot galvanizing process as well as welding types were analysed. It was found that the residual stress distribution of high strength steel welded tubes was flatter than the ones of ordinary steel tubes, and galvanizing process decreased the maximum residual tensile stress. Finally, the residual stress distribution model for steel welded circular tube sections was proposed which showed good agreement with the test results. Meanwhile, the finite element verification was carried out which provided reference for the future FEA of column buckling of high strength steel circular tubes. The research results provide foundation for the future study on the column buckling of welded steel circular tubes.