Study On Welding Deformation Control Of Square Flange-Plate Shell Structure

Welding deformation is always a problem to be faced with in the process of practical production,the complex structures with some big size,connecting the wall thickness of the plate is relatively small in size and lead to lower overall stiffness,It is easy to form large residual deformation under the not evenly heated and cooled,the uncoordinated plastic deformation of each region drived large deformation will influence to subsequent assembly accuracy,It is usually necessary to correct the deformation after welding.Therefore welding deformation is the key research content in welding structure.In this paper,the actual deformation of the rectangular flanged flange-plate shell structure in the production and processing of a large container made of Q235 A steel plate is analyzed.The welding process of this structure is simulated by MSC.Marc finite element simulation software,study the properties and mechanism of welding deformation of such structures,investigate the influence of welding sequence on the welding deformation of square flange.On that basis,apply different flame correction schemes on the minimum plane degree of the square flange surface,investigate the surface plane index of the square flange.The study found that:1.The finite element simulation results show that,the welding deformation of the square flange-plate shell structure is the result of the joint action of the Angle deformation between the flange and the vertical deflection of the structure.The former is caused by the difference of transverse shrinkage between the surface of fillet weld and welding root,in the flange length direction of the angle of deformation of about 1.32° angle,corresponding vertical wall maximum horizontal displacement of 0.8mm,width angle of about 0.97°,corresponding vertical wall maximum horizontal displacement of 2.6mm.While the latter is directly related to the fact that the fillet weld is located on one side of the neutral axis and the longitudinal shrinkage of the weld zone after welding produces an eccentric moment,flatness is about 6.1mm.Residual stress after welding mainly concentrated in the weld and near the seam area,the maximum residual stress is about 334 MPa,slightly above the material at room temperature yield strength value.The simulation results are in good agreement with the actual production and processing conditions,so as a follow-up optimization program reference.2.All kinds of optimized welding sequence programs have different degrees of influence on the flatness index of the square flange and the flange angle deformation: among them,the flange from the center of the width of the welding center to the length of the symmetrical welding,angle of the smallest deformation angle,the length of about 0.29°,corresponding vertical wall maximum horizontal displacement of 0.8mm,the width of about 0.37°,corresponding vertical wall maximum horizontal displacement of 1.0mm,but the worst flange flatness index,about 3.22mm;by the center of the length of the welding center to the width of the symmetrical welding,the angle of deformation is the largest,about 1.6° in the length direction,and about 0.74° in the width direction,but the flange flatness index is the best,about 1.75mm;Solder to the symmetry of the length/width center and the width/length center,Vertical wall angle deformation displacement and flange flatness indicators are living in the first two.From the square flange surface flatness indicators of the smallest point of view,determine the welding sequence from the center of the flange length to center width of the symmetrical welding,on the basis of follow-up flame correction.3.Apply a flame of the same width to the weld bead on the back side of the square flange-shell structure weld,use a heating sequence from the center of the length to the center of the width,the heating rate is 5.0mm/s,the average process temperature is about 700±20?,the vertical wall angle deformation displacement has a significant reduction.In the longitudinal direction of the square flange,the angle of deformation is reduced by about 1.37°,corresponds to the vertical wall of the maximum horizontal displacement value decreased 3.8mm and the angle of deformation in the width direction is almost completely corrected,decreasing by about 0.07°,corresponds to the vertical wall of the maximum horizontal displacement value decreased 0.2mm.4.In the width of the square flange width direction surface,adopted from the bottom up heating sequence,the heating rate is 1.0mm/s,the average process temperature is about 850±30?.The results show: square flange surface flatness dropped to about 1.14 mm,compared with the original deformation flatness decreased by about 81.3%.In the square flange-plate structure weld bead diagonal,apply a flame of the same width as the diagonal to correct,use a heating sequence from the center of the width to the center of the length,the heating rate is 5.0mm/s,the average process temperature is about 700±50?,after correction,the surface flatness of the flange is reduced to about 1.12 mm,compared with the original deformation flatness decreased by about 82%.According to the simulation results,reached the desired goal of reducing flatness by 60%,finally determine the square flange-shell structure of the suggestive welding process,through the actual production and processing verification.