Quantification of Ridging in Ferritic Stainless Steel Sheets by Electron Backscattered Diffraction R-Value Maps

Abstract: In ferritic stainless steel ~FSS!,undesirable surface defects of ridging appear during deep drawing.Theformationofthesedefectsisattributedtotheinhomogeneousdistributionoforientationsofindividualgrains.Inthe present work,a new electron backscattered diffraction R ~a!-value map was introduced,and the dependenceof the tensile directions on the formation of ridging in an FSS sheet was discussed using this map. The resultsshowedthatlargegraincoloniesinthe R ~a!-valuemapsleadtotheformationof severeridginginanFSSsheet. Key words: EBSD property map, R -value map,microtexture,ridging,Lankford parameter,ferritic stainless steel I NTRODUCTIONThe electron backscattered diffraction ~EBSD! equipmentinstalledinascanningelectronmicroscopeiswidelyutilizedto determine the microtexture and observe the microstruc-ture. The inverse pole figure ~IPF! map is a typical EBSDresult that displays the size, shape, and orientation of theindividual grains in the material ~Engler & Randle, 2010!.AnIPFmapdeterminedfromalargeareaprovidestheover-all distribution of orientations of the sample, i.e.,