Effect Of Electric Current Pulse On Solidification Structure Of Wheel Steel In The Continuous Casting Process

The wheel is one of the key parts of the train safety transportation,which also is one of the key parts of the train locomotive production process.As a new technology of environmental protection,electric current pulse processing technology can improve solidification structure.Therefore,it is necessary to study the effect of electric current pulse on the solidification structure of railway wheel steel by using wheel steel as the research object.The conclusions are as follows:(1)After the electric current pulse treatment,it can restrain the segregation of C elements in wheel steel,make the distribution of C elements more uniform.The effect of improving carbon segregation is related to to the pulse parameters.With the increase of energy(the current density and the pulse frequency),the C element distribution in wheel steel is more uniform,and its segregation is improved to a certain extent.(2)After the electric current pulse treatment,the growth of dendrites can be inhibited and the spacing of secondary dendrites is shortened.With the increase of energy(the current density and the pulse frequency),the spacing of twig dendrite is gradually shortened.(3)In the self-made electric current pulse water cooling model.Treating the dendrite of ammonium chloride by electric current pulse with 4V.The primary dendrite and the secondary dendrite stop growing,become thinner and shorter,and dissolved in solution.Treating the dendrite of ammonium chloride by electric current pulse with 12 V.The secondary dendrite was first broken,the primary dendrite is slowly dissolved and thinned,and then be broken.(4)The influence of current density and pulse frequency on the nucleation rate was further analyzed through calculation.The electric current pulse can reduce the nucleating potential barrier and increase the nucleation rate.The nucleation rate increases with the increase of current density and pulse frequency.(5)Through the industrial experiment,it is found that the solidification structure can be improved obviously by the current pulse treatment.When there is no appliedelectric current pulse,there is shrinkage cavity in the center part of casting billet,and after applying electric current pulse,shrinkage cavity disappeared,only porosity defects.As the current increases,the porosity decreases.And the equiaxed crystal ratio is also increased.