Research On Mechanical Properties Of Q690E Steel Plate And Welded Joint Based On Corroded Morphology

In recent years,high-strength steels are developed rapidly and the application are promoted in structures in our country.While the using of high-strength steel is not extensive for the corrosion problem.The tests and finite element simulations on mild steel and welded joints under stress corrosion are conducted at home and abroad.However,some of above researches are ideal and different with actual results.As a result,this paper adopts the method of the combination between tests and simulations to study the surface morphology of specimens under stress corrosion,the main contents are as follows:(1)Three groups of corrosion tests of Q690 E high-strength steel and welded joints are designed.The stress intensity and corrosion time are considered in tests,including different corrosion time,different corrosion time with the same stress intensity and different stress intensity with the same corrosion time.(2)The overall characteristic morphology parameters,such as the loss rate of mass and average thickness are preliminarily analyzed.The variation deciplines of them are studied with corrosion time and stress intensity.(3)Morphology of each specimen's gauge section under stress corrosion with ultra depth of 3D scanning system are obtained.The real morphology are restored with 3D point coordinate data.The surface morphology parameters are extracted and the variation disciplines of above under different factors are analyzed,such as roughness,pit corrosion depth and minimum cross section area and so on.(4)Uniaxial tensile tests are made to achieve the bearing capacity,elongation after fracture and total elongation under maximum force of specimens and the degradation of mechanical properties under varied factors are analyzed.The restored morphology are used to simulate the uniaxial tensile test of each specimen,and the feasibilities of the model are verified by comparing with the test results.Meanwhile,an appropriate simplified model was found to save the simulation cost.(5)Based on the surface parameters,the optimal parameters affecting bearing capacity and ductility of specimens are analyzed and the predicted results of mechanical properties about parameters are achieved.