Due to the high carbon and manganese content in high manganese steel Mn13, as-cast high manganese steel usually suffers from coarse solidification structure and carbide, which have a great detrimental effect on the high temperature mechanical properties of high manganese steel Mn13, and thus it is difficult to be produced by continuous casting process. In order to elucidate the solidification structure formation and carbide precipitation in the continuously cast slab of high manganese steel Mn13, several experiment methods, such as optical microscope (OM), electron backscatter diffraction (EBSD), field emission electron probe microanalyzer (EPMA), scanning electron microscope (SEM) and infrared C/S analyzer, and thermodynamic software Thermo-Calc were used to investigate the as-cast solidification structure, macro/micro solute segregation, and 2D/3D carbide morphology in the continuously cast slab of high manganese steel Mn13. The results show that the solidification structure of the Mn13 slab is mainly composed of coarse columnar crystals and the proportion of coarse columnar crystals is as high as 65.22 pct. The proportion of high angle grain boundaries (HAGB) in the equiaxed zone is 46.12 pct, but the proportion of HAGB in the columnar zone is only 11.98 pct. Both the C solute and Mn solute are rejected from the solid and enriched at the grain boundary, especially at the HAGB, where the growth direction of adjacent grains is quite different. The significant solute segregation and high grain boundary energy are both beneficial for the eutectic carbide formation and growth at the HAGB. Thus, the eutectic carbide is prone to form at the HAGB than the low angle grain boundaries (LAGB), and the thickness of the eutectic carbide at the HAGB is significantly thicker than that at the LAGB. The morphology of carbide from the slab subsurface to the center changes as follows: slender strip and small block → long strip and needle → long strip and lamellar. The secondary dendrite arm spacing (λ_II, μm) and the average carbide thickness (λ_c, μm), in the continuously cast slab of Mn13 steel, are formulated as functions of local cooling rate, (ν, °C s⁻¹), and determined by

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由于高锰钢Mn13中的碳和锰含量较高，铸态高锰钢通常存在粗大的凝固组织和碳化物，对高锰钢Mn13的高温力学性能有很大的不利影响，因此连铸工艺难以生产。为了阐明高锰钢Mn13连铸板坯的凝固组织形成和碳化物析出，采用光学显微镜（OM）、电子背散射衍射（EBSD）、场发射电子探针显微分析仪（EPMA）等多种实验方法，采用扫描电子显微镜（SEM）和红外C/S分析仪，以及热力学软件Thermo-Calc对铸态凝固组织、宏观/微观溶质偏析、高锰钢Mn13连铸板坯的2D/3D碳化物形态。结果表明，Mn13板坯的凝固组织主要由粗柱状晶组成，粗柱状晶的比例高达65.22%。等轴带中高角度晶界 (HAGB) 的比例为 46.12 pct，但柱状带中 HAGB 的比例仅为 11.98 pct。C 溶质和 Mn 溶质都从固体中排除并在晶界富集，特别是在 HAGB 处，相邻晶粒的生长方向完全不同。显着的溶质偏析和高晶界能都有利于共晶碳化物在 HAGB 的形成和生长。因此，与低角晶界（LAGB）相比，HAGB处的共晶碳化物更容易形成，并且HAGB处的共晶碳化物的厚度明显大于LAGB处的厚度。碳化物从板坯亚表层到中心的形态变化为：细条小块→长条针状→长条片状。二次枝晶臂间距 (Mn13 钢连铸板坯中的λ _II , μ m) 和平均碳化物厚度 ( λ _c, μ m) 表示为局部冷却速度 ( ν , °C s ^-1 ) 的函数，并由下式确定

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