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铁基12%Cr合金(质量分数)常被用来制造先进电机转子。电机转子要求材料具备良好的机械性能和细小的夹杂物,大尺寸的夹杂物通常会使得其性能恶化。本研究在缓冷试验后采用淬火工艺,保留了12%Cr合金液态冷却和凝固过程中形成的夹杂物,并通过扫描电子显微镜和能谱分析对夹杂物的形貌及化学成分进行了分析。结果表明:除各种氧化物夹杂外,在试样中观察到典型的氮化钛夹杂,但冶炼过程中并未添加钛元素。夹杂物析出的热力学计算结果表明:氮化钛夹杂析出于凝固末期,来自原料中痕量的钛元素即可导致氮化钛的析出,而氧化铝夹杂在液态合金中即可生成。通过控制钛元素和氧元素的含量在合理范围,有利于抑制凝固过程的夹杂析出。同时对凝固过程三氧化二钛夹杂析出的可能性进行了研究。
Iron-based 12% Cr alloy (mass fraction) is often used to manufacture advanced motor rotors. Motor rotors require materials with good mechanical properties and small inclusions, which often deteriorate their performance. In this study, the quenching process was adopted after the slow cooling test to retain the inclusions formed during the liquid cooling and solidification of the 12% Cr alloy. The morphology and chemical composition of the inclusions were analyzed by scanning electron microscopy and energy spectrum analysis. The results show that, in addition to various oxide inclusions, typical titanium nitride inclusions are observed in the sample, but no titanium is added during the smelting process. The results of thermodynamic calculation of inclusions show that the precipitation of titanium nitride precipitates at the final stage of solidification, and trace amounts of titanium from the raw materials can lead to the precipitation of titanium nitride, while the inclusion of alumina in the liquid alloy can be generated. By controlling the content of titanium and oxygen in a reasonable range, it is helpful to suppress the inclusion precipitation in the solidification process. At the same time, the possibility of inclusion precipitation of titania in the solidification process was studied.