Cofiño-Villar Alberto, Alvarez-Antolin Florentino, Asensio-Lozano Juan, Garcia-Garcia Maria
Materials Pro Group, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica, Universidad de Oviedo, Independencia 13, 33004 Oviedo, Spain.
Materials (Basel). 2019 Jan 8;12(1):185. doi: 10.3390/ma12010185.
This paper presents the results obtained regarding the control by manufacturers of the percentage, shape, and size of the precipitated graphite in the working layer of duplex work-rolls used in hot strip mill finishing stands. This working layer is manufactured in a martensitic white cast iron alloyed with Cr and Nb to promote the precipitation of M₃C and MC carbides, which provide a high wear resistance. The thermal cycling behavior of this layer also has a decisive influence on its service life. In this context, the percentage of graphite and its morphology play a very important role against said thermal cycling. With the aim of studying their effect on the sphericity of graphite, the analyzed industrial manufacturing factors worth highlighting include the liquidus temperature, the %Si, the use of an FeSi inoculant with traces of Lanthanum, inoculation with different amounts of FeB and SiCaMn, and the addition of Mg. At the periphery of the working layer, it was found that the use of the FeSi inoculant with traces of La promoted an increase in the density of counts of graphite, and that inoculation with FeB and the addition of 0.02% Mg diminished the nodularity of the graphite. Furthermore, throughout the entire thickness of the working layer, an increase in the amount of SiCaMn of up to 0.6 kg/T produced an increase in the size of the graphite particles and a marked improvement in their nodularity.
本文介绍了关于热轧带钢精轧机架使用的双相工作辊工作层中，制造商对析出石墨的百分比、形状和尺寸进行控制所取得的结果。该工作层采用与铬和铌合金化的马氏体白口铸铁制造，以促进M₃C和MC碳化物的析出，从而提供高耐磨性。该层的热循环行为对其使用寿命也具有决定性影响。在这种情况下，石墨的百分比及其形态对上述热循环起着非常重要的作用。为了研究它们对石墨球化率的影响，值得强调的已分析工业制造因素包括液相线温度、硅含量、使用含微量镧的硅铁孕育剂、用不同量的硼铁和硅钙锰进行孕育以及添加镁。在工作层的周边，发现使用含微量镧的硅铁孕育剂会促使石墨计数密度增加，而用硼铁孕育和添加0.02%的镁会降低石墨的球化率。此外，在工作层的整个厚度范围内，硅钙锰用量增加至0.6 kg/T会使石墨颗粒尺寸增大，并且其球化率有显著提高。
