Study On Welding Deformation For Low Alloy Stell Consider Solid State Phase Transformation

Welding is one of the most important methods in steel structure connection. It iswidely used in industries to assemble various products including structuralengineering, bridge engineering, automobile and so on. But welding deformationproduces the adverse effects to manufacturing accuracy and installation of structure. Ithas the important theoretical significance and engineering's application value to studyinfluencing factors of welding deformation, predicts and controls accurately weldingdeformation's method.The paper summarizes the interrelated theory and study method of steelstructure's temperature and stress-strain field. The characteristics and change rules ofmartensite and austenite transformation in HAZ are summarized on the basis ofchecking references, and deduces the volumetric strain formula of martensite andaustenite. The paper defines equivalent expansion coefficient of the weldingconsidering martensite and austenite transformation, the solid state phasetransformation is replaced by the equivalent expansion coefficient to realize numericalsimulations with ANSYS software considering solid state phase transformation'swelding deformation. The single layer and butted-weld of low alloy steel Q345iscalculated with finite element analysis software ANSYS, the thickness of low alloysteel is10mm. The rational temperature and residual stress field is obtained. Thetransverse shrinkage deformation and angular deformation without solid state phasetransformation is compared, the tendency of welding deformation with phasetransformation decreases. The influential factors of welding deformation is analyzed,it concludes phase transformation, welding speed, thickness and weld layer. Themulti-layer and butted-weld of low alloy steel Q345is calculated. The thickness is25mm and35mm.The paper studies distribution characteristics of welding temperatureand residual stress field, and the influential tendency of transverse shrinkagedeformation, longitudinal shrinkage and angular deformation is obtained. Theinfluential factors of butted-weld's welding deformation is studied, and the factors conclude welding speed, thickness and weld layer.