Effect of Nanophase on the Nucleation of Intragranular Ferrite in Microalloyed Steel  

作　　者：李新城 

机构地区：[1]Advanced Forming Technology Institute, Jiangsu University

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2010年第2期228-233,共6页武汉理工大学学报（材料科学英文版）

基　　金：Funded by the National Natural Science Foundation of China (50475125);the Universities Natural Science Fund Key Project of Jiangsu Province(04KJA430021)

摘　　要：MnS, MnS＋V（C, N） complex precipitates in micro-alloyed ultra-fine grained steels were precisely analyzed to investigate the grain refining mechanism. The experimental results shows that MnS, MnS＋V（C, N） precipitates provide nucleation center for Intra-granular ferrite （IGF）, so that refined grain remarkably. Moreover, substructures such as grain boundary, sub-boundary, distortion band, dislocation and dislocation cell in austenite increased as the deformation energy led by heavy deformation at low temperature （deformation temperature≤800 ℃, deformation quantity≥50%）. As a result, V（C, N） nanophase precipitated at these substructures, which pinned and stabilized substructures. The substructures rotated and transformed into ultra-fine ferrite. 20 nm-50 nm were the best grain size range of V（C, N） as it provided nucleating center for intragranular ferrite. The grain size of V（C, N） were less than 30 nm in the microalloyed steels that with volume ratio of ultra-fine ferrite more than 80% and grain size less than 4 μm.MnS, MnS＋V（C, N） complex precipitates in micro-alloyed ultra-fine grained steels were precisely analyzed to investigate the grain refining mechanism. The experimental results shows that MnS, MnS＋V（C, N） precipitates provide nucleation center for Intra-granular ferrite （IGF）, so that refined grain remarkably. Moreover, substructures such as grain boundary, sub-boundary, distortion band, dislocation and dislocation cell in austenite increased as the deformation energy led by heavy deformation at low temperature （deformation temperature≤800 ℃, deformation quantity≥50%）. As a result, V（C, N） nanophase precipitated at these substructures, which pinned and stabilized substructures. The substructures rotated and transformed into ultra-fine ferrite. 20 nm-50 nm were the best grain size range of V（C, N） as it provided nucleating center for intragranular ferrite. The grain size of V（C, N） were less than 30 nm in the microalloyed steels that with volume ratio of ultra-fine ferrite more than 80% and grain size less than 4 μm.

关 键 词：intra-granular ferrite （IGF） VANADIUM MNS NANOPHASE SUBSTRUCTURE 

分 类 号：TG142.15[一般工业技术—材料科学与工程]