Research On Key Industrial Technology Of Copper-based Rotor Slot Wedge For Generator

With the development of technology,the requirements for generator performance and reliability have exigent.The generator rotor is the core of the generator,and the slot wedge used to hold the rotor coil is a very important part.The components required to have high strength,high conductivity,high temperature resistance and impact resistance.Therefore,Cu-Ni-Si alloy is the most widely used slot wedge material with its excellent properties.Many factors affect the performance of Cu-Ni-Si alloy,such as the chemical composition,the amount of cold deformation,heat treatment,etc.In this paper,the effects of composition,cold deformation and heat treatment on the properties of Cu-Ni-Si alloys were investigated by spectrometer,scanning electron microscopy,optical microscopy,tensile testing at room temperature,hardness measurement.In addition,the influence of Equipment and mold parameters on the performance of the final product was discussed and the improvement suggestions were put forward.These are all in order to use the most effective means of industrialization to guarantee the excellent stability during the quantity production of the product.The main conclusions are shown as follows:1.With increasing amounts of La as an additive during casting,the columnar grains are obviously refined.Meanwhile,the dark second-phase particles are distributed from fine and uniform to coarse and independent,and gradually gather on the grain boundaries to form a strip distribution.This led to the Cu-Ni-Si alloy tensile strength and elongation first increased and then decreased.Finally,the optimal addition amount of La as a melting additive is 0.1 wt.%.2.Cu-Ni-Si alloy has central crack tendency.In order to avoid the use of traditional crystallizer to cause thermal cracking,red ingot casting is required.3.Cold deformation has a significant effect on tensile strength and hardness of the Cu-Ni-Si alloy.As the deformation increases,the dislocation density in the alloy increases,which promotes the more dispersed distribution of nucleation and precipitates of the aged precipitates.Thereby enhancing the strengthening of the substrate,so that the tensile strength and hardness of the alloy continue to increase,and gradually reduce the time to peak aging.To maximize productivity and lowest cost,we determine the amount of cold deformation of 50%while ensuring the performance.4.The differences in the performance of the various parts of the complex shape alloy are not only related to the deformation rate of each part but also to the distance from the part to the center.It is necessary to consider various factors and adopt a different deformation rate of each part to ensure balanced performance products.5.The cold forming Cu-Ni-Si alloy was subjected to aging at different temperatures for the same time.The results are shown as follows:When the temperature is lower than 430?,aging is the main process,and the mechanical properties gradually increase;when the aging temperature is above490?,the microstructure precipitates coarsen.Their mechanical properties were reduced,the micro-hardness was lower than 211HV,and the tensile strength was lower than 620MPa,which could not meet the practical requirements.Combined with the actual use,aging at from 430? to 460? can get good overall performance.6.The difference in the angle of the stretching die results in a different displacement of the outer layer of metal in the cross section of the alloy,thus affecting the hardness and stress at each point.According to the requirements of different products for different performance,the suitable mold should be selected.