Study On The Welding Effect Factors Of Upper Tool Holder Of Super Large Numerical Control Cutting Equipment

Now, with the development of aerospace, marine ship, rail transportation, steel structure, engineering machinery, nuclear power industry and other fields, the processing demand for large metal slab blank presented the trend of large increase, and then the demand of shears was suring, too. At the same time, the higher standard of machining accuracy as well as reliability of shears were proposed. The upper tool holder, the important component and direct stressed part of shears, would affect the machining accuracy, service life and quality after welding. On the basis of thermal elastic plastic finite element analysis and to build the tool holder three-dimensional finite element model in ANSYS environment, the welding process of upper tool holder was dynamic simulated and different factors that affect their welding process were discussed in this paper by using the sequential coupling analytical methods and the dead-live unit technology and APDL parametric programming technique.Firstly, the temperature field of upper tool holder in the welding process and evolution rule of residual stress in free constraint condition were obtained by using the dynamic simulation of welding process of upper tool holder. At the same time, the overall deformation rules of upper tool holder plate were focused studied. Results showed that:(1) There was high peak compressive stress value of upper tool holder appear in the heat affected zone and weld bead, and concentrated in which concentrated different bead in a different direction. What’s more, the maximum residual tensile stress occurs in the longitudinal direction;(2) Lateral compressive stress distribution range was the largest and the maximum compressive stress value appeared in the thickness direction;(3) The maximum displacement and distribution area of upper tool holder plate were different in different directions.Secondly, based on the understanding of stress field distribution during the process of tool welding, the influence regular of the phase transition, welding speed, different constraint conditions, welding sequence and other factors were discussed by using the method of thermal elastic plastic finite element. The results showed that:(1) The rest stress could be reduced in a certain extent when the occurrence of phase change, especially for the stress on the direction of the impact;(2) The relationship between residual stress peak value and speed was negative and the change of speed on the peak had a big influence on residual stress without influencing the distribution of stress;(3) The effects of different forms of constraint on the welding residual stress is complicated, of which the stress in the vertical direction of the weld was the greatest;(4) The impact of welding sequence for the value of residual stress of upper tool holder was not obvious.Finally, The deformation laws of vertical plate under different factors were analyzed and investigated. The result showed that:(1) The deformation trend was not affected by phase-change, while the stress of welds both the horizontal residual stress and the stress in thickness direction were decreasing.(2) The speed had no effect on the deformation trend of vertical plate and the deformation peak of vertical plate was negatively related to the speed.(3) Three different forms of restraint were presented along the Y axis "arch" bending deformation.(4) The impact of welding sequence for the deformation of vertical plate was not obvious, too.