Numerical Simulation And Experimental Study On Welding Of Drilling Shaker

Drilling shaker is the first level of solids control equipment to drilling fluid treatment. In the process of screening out large granular solid phase from drilling fluid, drilling shaker can not be replaced by other solids control equipment. Screen box is the vibration working part of vibrating screen whose main manufacturing process is welding. After welding, the screen box will produce deformations. Deformations will change the dimension and installation dimension of the screen box, leading to the vibrating screen assembly being difficult. At the same time, the centroid position of the screen box will change, influencing the preset vibration. In addition, the welding residual stress can affect the screen box structure intensity, shortening the lifetime of the vibrating screen. Therefore, the research of welding numerical simulation and experiment to the screen box is particularly important.Firstly, the screen box welding model was simplified by using the large-scale non-linear finite element software Marc2010in this paper. Besides, grid dividing, birth-death element and weld filler technologies have been simultaneously applied. The unit type, material characteristic parameters, the double ellipsoid heat source model and parameters have been determined. The welding temperature field boundary conditions and mechanical boundary conditions were also defined. Screen box welding finite element model was established and calculated. The maximum temperature of welding molten pool area was1500℃, reaching the melting point of Q235steel. The welding temperature gradient distribution of welding molten pool area, heat affected zone, away from the weld area parent metal, and in the parent metal were obviously formed. The result of welding residual stress was obtained after welding simulation. The maximum longitudinal residual stress was238MPa, reaching the material yield limit. The maximum transverse residual stress was about170MPa. The maximum equivalent residual stress was197MPa. The main deformation occurred in the screen box width direction, with maximum value was about1.58mm, The maximum overall deformation of screen box was about1.59mm.Secondly, according to the prediction of deformations and residual stress distributions, the screen box welding deformations control scheme was proposed, and the welding test was carried out. The screen box deformations were measured, the residual stress was calculated by using with the drilling method and high speed static strain gauge equipment. The deformation of the width direction was an average of about2mm, which was the primary deformation in the measure and meet the demand of screen box assembly and job requirements. Along the weld direction, the longitudinal residual stress was tensile stress, associating with stable distribution area, and a maximum value of221MPa. In the vertical direction of the weld, the farther away from the weld, the longitudinal residual tensile stress was smaller, and gradually transformed into compressive stress, The maximum compressive stress was119MPa. The transverse residual stress was showed to the further from the weld, the tensile stress was smaller, until to0.Finally, through the comparison and analysis, it was found that the Marc welding numerical simulation prediction and the test measured of the deformation values, and the residual stress distribution trend were similar. Vibrating screen assembly test well complied with the design requirements. It demonstrated that the simulation values were correct and showed that the numerical simulation prediction was the effective method to predict the deformation and residual stress of the vibrating screen welding. It not only showed that the set of welding technology and solutions of the vibrating screen box was feasible, but also verified that the deformation control scheme of the screen box was reasonable. Therefore, this paper studies is significant to control deformations and improve the welding strength of the vibrating screen.