Experimental research and analysis on residual stress distribution of circular steel tubes with different processing techniques

摘要

To investigate and model the residual stress in 345 and 420 MPa normal strength steel (NSS) as well as 690 MPa high-strength steel (HSS) circular tube sections, an experimental study with a total of 45 specimens was conducted using the hole-drilling and sectioning methods. The parameters altered during the experiment included the processing techniques, diameter-to-thickness ratios, steel strengths and welding locations. More than 3064 original test data samples were used to quantify the distribution characteristics of the residual stresses. The results suggest that the magnitudes and distributions of the residual stresses in the welded circular tubes were significantly affected by the processing techniques, steel strengths and welding locations, while no obvious correlation was identified with the diameter-to-thickness ratios. The maximum compressive residual stress ratio gradually decreased with an increase in the steel strength. However, the variation in the tensile residual stress near the weld seam in the middle section was not affected by the variation in the parameters, and its maximum value was in the range of 0.1 pi on both sides of the weld seam. Unlike those of the welded approach, the residual stresses along the circumferential direction of the inner or outer surfaces of the hot-rolled seamless circular steel tube sections were almost identical, which is basically consistent with the ECCS's theoretical model. On the basis of the test results, a distribution model and its simplified forms for NSS were established, and Yang's distribution model was further validated. The two distribution models can effectively describe the experimental results.