Numerical Analysis Of Cold And Hot Welding Temperature Field For Super Large Gears

As China has increased its investment in infrastructure,industry and other fields,the machinery industry has reached a critical period and needs a large number of heavy equipment.Traditional gear blanks are molded by casting.If ultra-large gears are still produced by casting,huge manufacturing costs will be incurred.Welding can now be used to produce higher-quality super-large gears that not only save on materials and manufacturing costs,but also increase production efficiency.As the gears are made of alloy steel,they have poor weldability and require high-temperature annealing after welding.If there is no good welding process control,cracks can easily occur.This paper starts with the thermal elastic-plastic theory and use ANSYS software to perform three-dimensional numerical simulation of the temperature field and stress field of the super gear welding.It is used to analyze the temperature field of the weldment,the stress field of the welding process and the residual stress caused by post-weld cooling.,and compared the effect of different preheating temperatures and welding speeds on them.This article mainly did the following research works:1.A three-dimensional finite element analysis model of moving heat source for the welding temperature field and welding stress field of super-large gears was established.To take both the calculation accuracy and the calculation speed into account,when the model is meshed,precise dimensions are adopted at positions close to the weld area,and rough positions are selected at relatively distant positions.Then delineate the appropriate time sub-steps,using ANSYS APDL language programming,to complete the "element death and live " and mobile heat source simulation welding deposition process.2.In this paper,the indirect method is used in the simulation calculation and only the one-way coupling effect of the temperature field on the stress field is considered.That is,the temperature field is calculated first,and then the welding stress field is calculated.This can save a lot of time and make the calculation process more reasonable and efficient.3.The results of simulations were used to analyze the distribution of the welding temperature field at different times and the thermal cycle curves at different points.The temperature field distributions at different preheating temperatures and welding speeds and the thermal cycles at specific points were compared.The preheating temperature and welding speed of the weld before welding have influenced the welding joints and heat affected zone,which provides an important basis for welding process improvement.4.When three-dimensional dynamic simulation of the welding gear stress field of the oversized gear is obtained,the distribution of different types of stress within the entire gear member and in the three major directions(axial,radial,and circumferential)is obtained,and the cloud image at any moment in the welding process can be viewed.