Characterization of MnS Particles in Heavy Rail Steels Using Different Methods
Characterization of MnS Particles in Heavy Rail Steels Using Different Methods
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DOI：
10.1002/srin.201600080
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发表时间：
2017-01
影响因子：
2.2
通讯作者：
Xuewei Zhang;Lifeng Zhang;Wen Yang;Yuan-chi Dong
中科院分区：
文献类型：
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作者：
Xuewei Zhang;Lifeng Zhang;Wen Yang;Yuan-chi Dong
采用传统的二维（2D）显微镜观察、三维（3D）显微CT检测和电解提取方法对U75V钢连铸（CC）大方坯和轧制钢轨中的MnS颗粒进行表征。讨论了MnS颗粒从铸坯表面到内部、柱状枝晶区内部以及铸坯等轴晶区的分布情况。MnS的形貌由靠近铸坯表面的椭圆形和球形逐渐向铸坯中心的条状、花瓣状、多面体状和不规则形转变。纯MnS夹杂物和由MnS外层和氧化物核心组成的复合夹杂物的尺寸从大方坯的边缘向中心逐渐增大。然而，MnS在轧制过程中沿轧制方向沿着伸长。细长MnS颗粒的横截面形貌在轨头和轨底呈球状和片状，在轨腰呈纺锤形。从热力学角度研究了MnS粒子的析出过程，计算结果表明，MnS粒子在凝固末期（固相分数fS = 0.94）生成，凝固过程中MnS粒子的数量受钢液中Mn和S的初始浓度的影响。
Characterization of the MnS particles in continuous casting (CC) blooms and rolled rails of U75V steel using the methods of traditional two‐dimensional (2D) microscope observation, three‐dimensional (3D) micro‐CT detection, and electrolytic extraction is performed. MnS particles from the surface to the interior, inside of columnar dendritic zone, and the equiaxed zone of the CC bloom are discussed. The morphology of MnS changes from elliptical and spherical near the surface of bloom to strip‐like, petal‐like, polyhedral, and irregular in the center of bloom gradually. The size of both pure MnS particles and complex inclusions which consist of a MnS outer layer and an oxide core increase from the edge to the center of bloom. However, MnS is elongated along the rolling direction during rolling process. The morphology of the cross section of the elongated MnS particles presents as globular and flaggy shape in the head and bottom of rail, and spindle shape in the waist of rail. The precipitation of MnS particles is studied on the basis of thermodynamics, the calculating results show that MnS particles are generated towards the end of solidification (solid fraction fS = 0.94), the amount of MnS particles are affected by the initial concentration of Mn and S in molten steel during solidification.