Mechanism Research About Effect Of Predeformation And Grain Boundary On Bake Hardening Properties In Low Carbon Steel

The cold rolled low carbon steel was annealed with differentprocess. The Sample after annealing treatment was predeformed andbaked, bake hardening properties is measured. Measured the grainboundary structure and component distribution of the sample by usingelectron backscatter diffraction technology and electron probe technology,measured the sample by using internal friction technology. Internalfriction under the different process was measured by technique of internalfriction Researched the bake hardening mechanism by using all theexperimental results. The main results are as follows:The experimental steel under the predeformation of2%~10%.Withthe predeformation increasing, BH value rises, low angle grainboundaries grow, the change to low ΣCSL grain boundaries and higeΣCSL grain boundaries are not obvious, generally high angle grainboundaries have large quantity. Grain boundary segregation of carbonelement increase.Along with the average grain size increasing, BH value decrease, thechange of the average grain size, did not have many effects on grainboundary character distribution. Grain boundary segregation of carbonelement increase.Under the predeformation of2%~10%, the SKK internal frictionpeak of the samples increase along with the increase ofpredeformation, the same as BH value. Grain boundary internal frictionpeak increase along with the increase of predeformation.Under the2%predeformation，research the sample in different grainsize. The SKK peak of annealing2min and the original samples decreasewith the increase of grain size. While the SKK peak of the sampleincrease. With the increase of grain size, grain boundary peak valuedecrease.