RE Strengthening And Cross Section Optimization Of I-beam Steel

I-beam has been widely used in modern steel structure engineering because of its good structural characteristics and mechanical properties.It is one of the most widely used section steels in steel structure engineering.However,when arc shaped steel is used in the dome of tunnel and Bridge in the field of cold bending technology,cracking occurs in the process of cold bending because of its high content of non-metallic inclusions,low plasticity and unreasonable design of section parameters.In order to improve these problems,shot peening technology is used to improve the residual stress state and mechanical properties of I-beam surface.The samples after shot peening are tested for surface stress,surface hardness and surface morphology.I-beam is melted,and trace rare earth cerium(Ce)element is added to the molten steel to modify the molten steel,and the test after rare earth modification is carried out.The mechanical properties,metallographic structure and SEM of the samples were analyzed.The section of I-beam was optimized by ANSYS finite element analysis software,and the position of maximum stress and strain was simulated.The section of I-beam during cold bending was optimized.The main results are as follows:1.The better shot-peening process is 25 seconds under the pressure of 0.4 MPa.The diameter of shot-peening is constant at 1.2 mm,the bending strength after shot-peening is 799.82 MPa,which is 16% higher than that of non-shot-peening sample at 689.33 MPa,the surface hardness after shot-peening is 315.67 Hv,which is 75% higher than that of non-shot-peening sample at 190 Hv,and the thickness of the strengthened layer introduced by shot-peening is about 1.2 mm,and the residual compressive stress on the sample surface after shot-peening is increased by 16%.The average value increased by about 300 MPa.2.The content of S element decreases with the increase of rare earth cerium content in I-beam steel.When the content of rare earth is 0.08%,the content of S element decreases to 0.005%,which is 10 times lower than that of raw materials.The rare earth cerium(Ce)element can purify S i,P,S and impurity elements in molten steel to a certain extent.The elongation ofsamples modified by rare earth is relative to raw materials under the condition of guaranteeing yield strength.The yield strength can reach 356.26 MPa,which is 15.3% higher than that of the original sample.3.ANSYS finite element analysis software is used to optimize the beam section of No.16I-beam.The yield strength of I-beam is improved after rare earth modification and shot peening strengthening.Under the premise of guaranteeing the strength of steel beam,the section area and weight can be reduced by 13.5% and the maximum tensile stress can be reduced by 12.3% without increasing the mass in cold bending simulation.4.A single arch model of 16# I-beam is established and its curvature radius is optimized.When the horizontal distance at the bottom of the single arch is 5 meters,the optimal curvature radius is 5 meters.