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采用Al-Mg、V-Ti和Al-Mg+V-Ti对3.81wt%C-15wt%Cr铸铁进行变质处理,研究不同变质剂对高铬铸铁初生碳化物的变质机理。结果表明,Al-Mg变质的机理主要表现为脱氧脱硫净化铁液,增加形核的过冷度。低密度的脱氧和脱硫产物在上浮过程中扰乱了液态原子排列,把碳化物形核温度推向了更低的温度,但Al-Mg对初生碳化物的变质作用有限,碳化物仍然呈板状且尖角突出,碳化物尺寸稍有减小。经V-Ti变质处理后,高铬铸铁初生碳化物呈多边形状或条状,形貌和尺寸明显改善。其变质机理主要为V、Ti加入后增加了碳化物的异质形核核心,细化了碳化物。Al-Mg+V-Ti对高铬铸铁的变质效果最好,初生碳化物为细小的六边形,分布较为均匀,主要是Al-Mg净化铁液和V-Ti增加形核率共同作用的结果。
The modification of 3.81wt% C-15wt% Cr cast iron with Al-Mg, V-Ti and Al-Mg + V-Ti was carried out to study the metamorphic mechanism of the different modifiers on the primary carbides of high chromium cast iron. The results show that the mechanism of Al-Mg metamorphism mainly deoxidized desulfurization to purify molten iron and increase the undercooling of nucleation. Low-density deoxygenation and desulfurization products disrupt the arrangement of liquid atoms in the process of floating, and push the nucleation temperature of the carbide to a lower temperature. However, Al-Mg has limited metamorphism of the primary carbides and the carbides are still in the form of plate And sharp corners, carbide size slightly reduced. After V-Ti metamorphism treatment, the high-Cr cast iron primary carbides are polygonal or strip shape, morphology and size significantly improved. The metamorphic mechanism is mainly V, Ti added after heterogeneous nucleation of carbide nucleation, refinement of the carbide. Al-Mg + V-Ti has the best effect on the modification of high-chromium cast iron. The primary carbides are small hexagons with a uniform distribution. Al-Mg + V-Ti is mainly responsible for the synergistic effect of Al- result.