| New energy vehicles are an inevitable trend in the future development of the automotive industry.As the core component of new energy vehicles,the key performances of vehicle driving are determined by the drive motor system.The non-oriented electrical steel sheets,which is the key material of the driving motor,have a great influence on the driving characteristics and service performance of the motor.When the electrical steel stator and rotor laminations are processed,the punching and shearing edge effect would introduce residual stress,which could lead to the deterioration of the magnetic properties of the non-oriented electrical steel laminations.In view of this engineering problem,the effect of shearing methods on the edge structure and morphology of three types of ultrathin non-oriented electrical steel sheets has been investigated,and the effects of annealing temperature and time on the texture,magnetic domains and magnetic properties of ultra-thin non-oriented electrical steel sheets have been studied.The conclusions are as follows:(1)The variations of shearing method have a great influence on the morphology and structure of the ultra-thin non-oriented electrical steel sheet.Compared with sheet metal shears and wire cutting,the edges of the electrical steel sheet prepared by the shearing machine are straight without obvious burrs.The micro morphology showed that plastic deformation happened obviously along the shear edge of the electrical steel sheet sheared by the shearing machine.(2)Annealing treatment led to recovery and recrystallization in the edge deformation area of ultrathin electrical steel sheet,and the increase of annealing temperature induced the gradual growth of recrystallized grains.In addition,the annealing treatment caused the decrease of the microhardness of electrical steel sheets.In particular,the edge hardness was greatly reduced,which was similar to that of the undeformed area.The residual stress at the shear edge was released.(3)The variations of annealing time and temperature had a great influence on?*and?fiber textures in three kinds of ultrathin electrical steel sheets.After annealing treatment at 750?or 800?for 1 h,the unfavorable{111}<112>and{111}<110>textures in ES20 electrical steel sheets were weakened.After annealing at 700?for 1 h,the ES25 electrical steel sheet has a{110}<001>Goss texture that is beneficial to improving its magnetic properties.After annealing treatment at 750?for 1.5 h,the{111}<112>texture in ES27 electrical steel sheet was transformed into S{023}<634>texture,and the{111}<110>texture was transformed into{111}<143>Texture.(4)The variations of annealing time and temperature had a great influence on the magnetic domain structure of three kinds of ultrathin electrical steel sheets.After annealing treatment at 800?for 1 h,it is found that the magnetic domain structure of ES20 samples mainly consisted of 180°domains,and 90°domains basically disappeared.Compared with the as-received ES20 samples,the magnetic domains were more uniform and finer with the increases of magnetic domain density.After annealing at 750°C for 2h,the 180°domains of ES25 samples were fully refined.Its magnetic domain direction in a single grain was consistent,the domain wall was slender and the width became narrow.After annealing at750?for 1.5 h,the main domains of ES27 samples were mainly composed of 180°domains,and the number of 90°domains was greatly reduced.the magnetic domain spacing became smaller,and the density increased.(5)After annealing treatment,the magnetic properties of ultrathin non-oriented electrical steel sheets can be improved to varying degrees.Take ES25 electrical steel sheets for example,after annealing treatment at 750?for 2 h,ES25 samploes showed the minimum iron loss values P1.0/50and P1.5/50,where P1.0/50was reduced to 0.52W/kg,13.79%lower than that of the as-received ES25 samples,and meanwhile P1.5/50was reduced to 1.21W/kg,showing a decrease of 12.95%.The maximum magnetic induction intensity of ES25samples can be obtained after annealing treatment at 800?for 1 h,which was 32.3±0.3Gs,0.7 Gs higher than that before annealing,which meets the performance requirements of electrical steel sheets for new energy vehicles. |
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