Pearlite refining is one of the most used methods to increase the strength of cast irons, and it can be achieved using different strategies. In this work, three strategies to obtain pearlite refining were applied to a given hypoeutectic gray cast iron centrifuged in a coated steel mold: (1) increasing the Cu, Mo and Cr contents; (2) intensifying the cooling rate of the metallic mold; and (3) cooling of the cast iron with forced air. Strategies 2 and 3 aimed to increase the cooling rate during the eutectoid reaction. Then, four experiments were conducted: a reference experiment and other three applying separately the strategies above. Materials samples were characterized by optical metallography, chemical analyses, microhardness, pearlite interlamellar spacing measurements and tensile tests. The metallographic examination did not show any important change in the graphite morphology. The pearlite interlamellar spacing and microhardness were computed as distribution curves from at least thirty measurements in the materials matrices. These curves showed a decrease in pearlite interlamellar spacing and an increase in pearlite microhardness for the three materials in which the pearlite refining strategies were applied as compared to the reference material. The mean pearlite interlamellar spacings were reduced from 0.10 μm for the reference material to 0.07 μm, 0.08 μm and 0.08 μm for the materials in which strategies 1, 2 and 3 were applied, respectively. The UTS increased from 378 MPa for the reference material to 423 MPa, 418 MPa and 390 MPa for the strategies 1, 2 and 3, respectively.

中文翻译：

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亚共晶灰铸铁的珠光体精炼策略

珠光体精炼是提高铸铁强度的最常用方法之一，可以使用不同的策略来实现。在这项工作中，将三种获得珠光体精炼的策略应用于在涂层模具中离心的给定的亚共晶灰口铸铁：（1）增加Cu，Mo和Cr的含量；（2）提高金属模具的冷却速度；（3）用强制空气冷却铸铁。策略2和3旨在提高共析反应期间的冷却速率。然后，进行了四个实验：参考实验，另外三个分别应用上述策略。通过光学金相，化学分析，显微硬度，珠光体层间间距测量和拉伸试验对材料样品进行了表征。金相检查没有显示出石墨形态的任何重要变化。珠光体的层间间距和显微硬度是根据材料矩阵中至少30次测量得到的分布曲线计算的。这些曲线表明，与参考材料相比，采用珠光体细化策略的三种材料的珠光体层间间距减小，珠光体显微硬度提高。平均珠光体层间间距从参考材料的0.10μm减小到应用策略1、2和3的材料的0.07μm，0.08μm和0.08μm。UTS从参考材料的378 MPa分别增加到策略1、2和3的423 MPa，418 MPa和390 MPa。珠光体的层间间距和显微硬度是根据材料矩阵中至少30次测量得到的分布曲线计算的。这些曲线表明，与参考材料相比，采用珠光体细化策略的三种材料的珠光体层间间距减小，珠光体显微硬度提高。平均珠光体层间间距从参考材料的0.10μm减小到应用策略1、2和3的材料的0.07μm，0.08μm和0.08μm。UTS从参考材料的378 MPa分别增加到策略1、2和3的423 MPa，418 MPa和390 MPa。珠光体的层间间距和显微硬度是根据材料矩阵中至少30次测量得到的分布曲线计算的。这些曲线表明，与参考材料相比，采用珠光体细化策略的三种材料的珠光体层间间距减小，珠光体显微硬度提高。平均珠光体层间间距从参考材料的0.10μm减小到应用策略1、2和3的材料的0.07μm，0.08μm和0.08μm。UTS从参考材料的378 MPa分别增加到策略1、2和3的423 MPa，418 MPa和390 MPa。这些曲线表明，与参考材料相比，采用珠光体细化策略的三种材料的珠光体层间间距减小，珠光体显微硬度提高。平均珠光体层间间距从参考材料的0.10μm减小到应用策略1、2和3的材料的0.07μm，0.08μm和0.08μm。UTS从参考材料的378 MPa增加到策略1、2和3的423 MPa，418 MPa和390 MPa。这些曲线表明，与参考材料相比，采用珠光体细化策略的三种材料的珠光体层间间距减小，珠光体显微硬度提高。平均珠光体层间间距从参考材料的0.10μm减小到应用策略1、2和3的材料的0.07μm，0.08μm和0.08μm。UTS从参考材料的378 MPa分别增加到策略1、2和3的423 MPa，418 MPa和390 MPa。参考材料为10μm，应用策略1、2和3的材料分别为0.07μm，0.08μm和0.08μm。UTS从参考材料的378 MPa分别增加到策略1、2和3的423 MPa，418 MPa和390 MPa。参考材料为10μm，应用策略1、2和3的材料分别为0.07μm，0.08μm和0.08μm。UTS从参考材料的378 MPa分别增加到策略1、2和3的423 MPa，418 MPa和390 MPa。