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对导致易切削钢38MnVS中硫化锰分布不均匀的硫偏析进行了模型研究。模型中考虑了凝固方式转变、MnS的析出过程,讨论了凝固过程中碳、硅、锰、磷和硫的偏析变化以及碳、锰、硫含量和冷却速度对凝固末期枝晶间硫偏析的影响。结果表明:碳含量对枝晶间偏析有显著影响,w(C)在0.1%~0.5%时,硫偏析随铁素体形成量增加而减小,随奥氏体形成量增加而增加;硫含量的增加加剧了凝固末期硫在枝晶间富集,提高锰含量和冷却速度有利于抑制硫偏析。
The model of sulfur segregation caused by the uneven distribution of manganese sulfide in free-cutting steel 38MnVS was studied. In this model, the transition of solidification mode and the precipitation process of MnS are considered. The segregation changes of carbon, silicon, manganese, phosphorus and sulfur and the influence of carbon, manganese and sulfur content and cooling rate on the dendritic segregation during the final solidification phase are discussed . The results show that the carbon content has a significant effect on the segregation between dendrites. When w (C) is between 0.1% and 0.5%, the segregation of sulfur decreases with the increase of ferrite formation and increases with the formation of austenite. The increase of the content aggravates the enrichment of sulfur in the interdendrites at the end of the solidification. Increasing the content of manganese and cooling rate is favorable for inhibiting the sulfur segregation.