Numerical Simulation Of Temperature Field And Residual Deformation On Welding Process Of Super Alloy Components

Welding is a non-equilibrium complex process of heating and cooling,weld zone and its neighborhood surfing from workplace surrounding constraints and can’t completely free contraction. After welding, there is the residual stress and the residual deformation in the workplace, so the welding quality and structure size is hard to be guaranteed. While, a certain superalloy component is welded from an large complex thin-walled shell part with four grooves on outside wall and sheet as same as groove shape. Due to weld is longer and relatively concentrated, and using TIG welding method have residual stress and welding deformation is large after welding. Consider mainly base deformation reached2.0mm, and dissatisfy with the design requirement of deformation is not more than0.8mm. Therefore, this paper using the finite element method, numerical simulation research of temperature field and residual deformation on welding process of superalloy components, in order to obtain reasonable welding process parameters, for predictiing and controlling superalloy components welding deformation has important guiding significance. The main research contents and the results are as follows:Base on CATIA3D modeling software, the geometrical model was built, the mesh model was established by using Visual Mesh software. So, the finite element model of superalloy components and overlap joint were established. At the same time, the database of thermal property and mechanical property of superalloy K4169was established.Based on the finite element model of overlap joint, effect of the different welding speed on temperature field, residual stress and residual deformation of overlap joint by using double ellipsoid heat source model.The results show, when the other welding parameters keep constant, as the welding speed increasing, the size of weld pool, fusion area and heat affected zone decrease, meanwhile, the peak temperature of each node of welding center reduce with increase of welding speed. As the welding speed increasing the residual stress first decreases and then increase, the residual deformation reduces gradually.Analyze the effect of the welding speed of temperature field and residual deformation on welding process of overlap joint The optimal welding parameter is obtained, welding current is50A, welding voltage is13V and welding speed is3mm/s.Based on the finite element model of superalloy components, the size and distribution rules of temperature field, residual stress and residual deformation of welded structure were researched. The results show, the welding sequence is large effect for deformation of welded structure, adopting the welding sequence of W4-W1-W3-W2can be obtained minimum residual deformation.Base on the welding sequence of W4-W1-W3-W2for a certain improvement, that is in long weld and large deformation was fixed by spot welding, welding the one weld after cooling60s and then the next seam welded. The improved results are shown that, the total deformation of welding structure is about1.5mm; the deformation shell base is about0.5mm, which can satisfy the design requirement.