摘要:
通过实验研究了氧含量对硫化物形态的影响.结果表明:随着氧含量的增加,MnS夹杂物的形态由Ⅱ类向Ⅰ类转变,其平均直径和面积分数增大,数量减少,长宽比减小.通过数学模型以及Fe-Mn-S和Fe-Mn-S-O体系的四元相图研究了氧含量对硫化物形态产生影响的机理.在氧质量分数高达0.022%时,凝固初期形成了大量的MnO系低熔点液态氧化物,促进了MnS的形成方式从共晶方式向偏晶方式转变,形成Ⅰ类MnS;氧质量分数在0.01%以下时,凝固初期形成的MnO系低熔点液态氧化物较少,大部分MnS是在凝固末期以共晶形式析出,形成Ⅱ类MnS.
关键词:
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易切削钢
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夹杂物
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硫化锰
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形态
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相图
Abstract:
The effect of oxygen content on the morphology of sulfides was investigated by experiment. Experimental results show that the morphology of MnS inclusions changes from Type 11 to Type I with increasing oxygen content, the diameter and area fraction of MnS inclusions increase, but the number and mean aspect ratio of MnS inclusions decrease. The influence mechanism of oxygen content on the morphology of sulfides was studied on the basis of the mathematic model, the Fe-Mn-S ternary system diagram and the Fe-Mn-S-O quaternary system diagram. In the case of the oxygen mass fraction up to 0.022%, the liquid low-melting oxides rich with MnO were found at the early stage of solidification, these oxides made the formation behavior of MnS from eutectic reaction to monoteetic reaction, and Type I MnS formed. In the case of the low oxygen content less than about 0.01%, little liquid low-melting oxides rich with MnO were found at the early stage of solidification, most of MnS precipitated in an euteetie mode at final solidification, and Type Ⅱ MnS formed.
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