Sulfur is added to low-alloyed steel FAS3420H to improve the free-cutting property of the steel. Elongated MnS inclusions usually deteriorate the mechanical and process performance of steels, so the control of shape and size of MnS is essential. The statistical analysis of MnS inclusions in as-cast and rolled steels at different positions shows that the distribution and aspect ratio of MnS in rolled steel are closely related to the quantity and size of MnS in as-cast one. The in situ observation and experimental results reveal that homogenization treatment effectively reduced MnS inclusions size and transformed their shape to globule or ellipsoid. Significant change of quantity and size of MnS inclusions was identified only when the soaking time exceeds 5 h at 1,250℃. Additionally, a kinetic model is presented to quantitatively characterize the behavior of MnS inclusions during homogenization process.

中文翻译：

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低合金钢FAS3420H均质过程中MnS夹杂物的行为

向低合金钢FAS3420H中添加了硫，以提高钢的易切削性。伸长的MnS夹杂物通常会降低钢的机械性能和加工性能，因此控制MnS的形状和尺寸至关重要。对铸态和轧制钢中不同位置的MnS夹杂物的统计分析表明，铸态中MnS的分布和纵横比与铸态中MnS的数量和尺寸密切相关。原位观察和实验结果表明，均质处理有效地降低了MnS夹杂物的尺寸，并将其形状转变为球状或椭球形。仅当在1,250℃下均热时间超过5 h时，才发现MnS夹杂物的数量和大小有显着变化。此外，