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本文从稳定地制取高蠕化率蠕铁和开拓蠕铁新的孕育剂的目的出发,对稀土-Si-Ca系蠕铁采用几种不同的添加物进行了孕育处理,试验结果表明,Si-Zr复合孕育剂在达到单-75%硅铁相同的孕育效果下,其加入量仅为后者的1/4～1/3。单-Si-Ca和单-Si-Ba孕育时,白口倾向均大於单-Si-Fe,且蠕墨大小的均一性变差。当Si-Ba配入少量Zr时,其蠕化率有所提高,白口倾向缓和。试验指出,单纯用1#稀土或重稀土孕育时,即使加入少量,白口倾向极为强烈。这与其在灰铁中有良好的孕育效果大相径庭。但若向75%硅铁中酌量配入1#稀土,用于孕育φ100mm以上厚壁蠕铁件时,却有使蠕墨形体匀称、孕育效果改善之功效。文中认为,蠕铁良好的石墨化孕育的主要判据应为:渗碳体小于1%,蠕化率≥80%,且蠕墨形体匀称、大小趋向均一、匀布。对单-75%硅铁孕育时的不同加入量和不同孕育温度进行对比试验后提出,为了稳定地获得高蠕化率的蠕铁,应遵遁“适量、适时”的孕育原则。
In this paper, starting from the purpose of stably preparing high-creep rate of vermicular iron and developing new inoculant of vermicular graphite, rare-earth-Si-Ca based vermicular iron was inoculated with several different additives. The experimental results show that Si -Zr composite inoculant reached the same inoculation effect of single-75% ferrosilicon, the amount added was only 1/4 ~ 1/3 of the latter. The mono-Si-Ca and mono-Si-Ba inoculation tended to be more white than mono-Si-Fe, and the uniformity of the vermicular graphite became worse. When Si-Ba with a small amount of Zr, the rate of increase of its whiteness, white tend to ease. Tests showed that simply using 1 # rare earth or heavy rare earth incubation, even with a small amount of white tendencies are extremely strong. This is quite different from its good inoculation in gray iron. However, if the 75% ferrosilicon into 1 # rare earth, used to nurture more than φ100mm thick vermicular iron pieces, there are so vermicular graphite shape, inoculation effect to improve the effectiveness of. The article holds that the main criterion for the good graphitization of vermicular iron should be as follows: the cementite is less than 1%, the vermicularity rate is more than 80%, and the shape of vermicular graphite is uniform and the size tends to be uniform and uniform. After comparing the different addition amount and different incubation temperature of single-75% ferrosilicon, it was suggested that in order to get stable vermicular iron with high vermicular rate, the principle of “appropriate amount and timely” should be followed.