Experimental And Model Investigation On Residual Stresses In Welded Thick-walled Box-shaped And H-shaped Sections Fabricated From Q460GJ

The new concept of architectural design has led to the diversification of architectural forms,with steel structures increasingly appearing in people's daily lives.The continuous emergence of large-span and ultra-high-rise steel structure buildings has made domestic GJ steel usher in development opportunities.Because of its excellent characteristics,domestic GJ steel plays an important role in the construction of major domestic projects.Q345 GJ,Q460GJ have been applied to some practical projects,but the research work on GJ series steels for building structure is still relatively lagging behind,especially for the study of thick-walled components,which will lead to irrational design and waste of high quality steel.The stability,fatigue strength and brittle fracture of components are affected by the residual stress,so the residual stress is an important factor in the design and analysis of the component level.The new steel structure design standard(GB50017-2017)is about to be implemented,and Q345 GJ has also been introduced,but the related research on the residual stress and mechanical properties of Q460 GJ steel is not comprehensive enough,which will affect the overall promotion of GJ steel.Based on the National Natural Science Foundation of China(No.: 51578089),this paper investigates the residual stress of Q460 GJ steel thick-walled welded box and H-shaped section.The main contents of this paper include:(1)Static material tests were performed on 42 mm and 80 mm thick Q460 GJ steels.Through the uniaxial tensile test,some mechanical parameters and corresponding stress strain curves of two kinds of thickness steel plates were obtained.(2)The longitudinal residual stress of 80 mm thick-wall welded box and H-shaped cross-section of Q460 GJ steel was measured by cutting method and corrected by straightening measurement.(3)Through the residual stress test results and distribution,analyze the possible errors of this test and the factors that affect the test results.(4)Use layered cutting to explore changes in the longitudinal residual stress along the thickness of the section.The result of the experiment was plotted by MATLAB software.From the figure,the change of residual stress along the thickness direction of each section of the section can be observed more intuitively.(5)The existing residual stress distribution patterns are summarized,the results of this experiment are fitted,the residual stress distribution pattern is proposed,and the existing model closest to this model is found,and the specific differences between the two are carefully analyzed.The innovation of this article:(1)For the first time,the plate thickness of the Q460 GJ steel welded box section and H-shaped section residual stress was increased to 80 mm,filling the Q460 GJ steel residual stress study at this thickness blank.(2)Drilling steel plate for the first time using a finishing drilling platform can improve drilling efficiency and hole formation quality.(3)A simplified distribution model for residual stress of Q460 GJ steel is proposed,and a large number of existing residual stress distribution patterns are summarized,and the proposed model is compared with the proposed model.