Numerical Analysis And Control Of Welding Deformation Of Excavator Rotary Platform

Rotary platform(rotary table)is the carrier connected with the excavator working device and walking mechanism,is an important part of the excavator,its quality directly affects the service life.The production and manufacture of rotary platform mostly adopts welding for general assembly.Due to the large number of T-shaped joints,the welding structure has a large degree of restraint.After assembly,it is easy to cause welding deformation and affect the work of excavator.In order to improve the flatness of the rotary platform and prolong its service life,the finite element method was used to simulate the influence of different welding sequence and welding heat input on the deformation of the rotary platform,and the main influencing factors of the platform deformation were analyzed and tested,and the improvement measures were put forward.The results are as follows:Taking the T-joint as the research object,the research results show that the single-layer welds in the rotary platform welding structure can reduce the welding deformation by adopting the welding direction from the outside to the inside and from the top to the bottom,and the cross fillet welds can meet the actual production requirements by adopting the welding direction from the opposite to the inside.When the double welds are in the same direction to the right,the deformation can be obviously reduced due to the restraint of the groove section steel.Based on the determination of welding direction,the design optimized the welding sequence of different welds,and the bottom plate deformation of the rotary platform could be controlled to 1.058mm,which was significantly reduced(12%)compared to the original order of 1.202mm.The influence of welding heat input on the flatness of rotary platform was studied on the basis of optimal welding sequence.When the welding current is controlled at 280A,the deformation of the rotary platform can be effectively reduced,and the deformation is 1.058mm,which meets the welding quality requirements.Welding speed control is 5mm/s,can ensure the welding quality and reduce the deformation,and is conducive to welding operation.Through the comparison between the experimental test and the simulation calculation,the simulation results are consistent with the experimental values,and the welding deformation amplitude is reduced by 14.8%.On the basis of controlling welding sequence and welding heat input,other factors affecting the deformation of rotary platform,such as reverse deformation,pre-welding assembly and inter-layer temperature,were analyzed.The test results show that the deformation caused by welding can be effectively offset by controlling the reverse deformation of 2.5mm.The welding deformation can be reduced by controlling the deformation of 1.2mm before and after welding.The deformation can be reduced by controlling the interlaminar temperature of the close weld less than 60?.By comprehensively controlling the above influencing factors,the welding test of the rotary platform was carried out,and a small flatness of 0.774mm was obtained,which verified the effectiveness of the improved deformation measures of the rotary platform.