Investigation of the Annealing Texture Variations on different Through-thickness Depths at Fully Recrystallized State in a Cold-Rolled Non-oriented Electrical Steel

• Main Authors: Po-Yi Cheng, 鄭柏毅
• Other Authors: Pei-Ling Sun
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/3p79fe

碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 107 === This study mainly aims on the recrystallization texture evolutions of non-oriented electrical steels (NOES) during annealing treatment and investigations the differences of through-thickness recrystallization textures along normal direction (ND). The 1.24 wt.% Si 78% cold rolled NOES, which were hot band annealed by BA (batch annealing) and APL (annealing pickling line) were used. The specimens were first ground to the specific thicknesses along the ND direction, which are 99%, 87.5%, 75%, 62.5%, and 50%, respectively and annealed at 700℃ subsequently (grinding and annealing treatment, GA). The results of other researchers are inclucluded here for comparsions,in which the specimens were first annealed at 700℃ and ground to the specific thicknesses along the ND direction, 99%, 87.5%, 75%, 62.5%, and 50%, respectively in sequence (annealing and grinding treatment, AG). The purpose of using these two sets of specimens (GA and AG) is to study the influence of surface effect on the recrystallization textures. The macrotextures were analyzed by X-ray diffraction and the result show that stronger Goss intensity appears in the GA specimens than in the AG specimens. It is observed that the intensities of Goss and {111}<112> orientations are complementary to each other along the through-thickness direction in both BA and APL conditions. The microtexture examinations of specimens (TD surface) were carried out by electron backscattered diffraction (EBSD). It can be found that more Goss grains recrystallize near the specimen surface in the GA treatment. The location with the highest area fraction of Goss recrystallized grains are in the thicknesses between 75% and 87.5%. The results of Ex-situ experiments indicate that more Goss recrystallized grains appeared at sub-surface which contains dense γ-fiber grains and shear bands in the deformed state. The Goss recrystallized grains mostly concentrate in the {111}<112> deformed grains on the surface of the GA specimens. Furthermore, the aggregation of Goss recrystallizd grains near surface can be found in the BA steel.