降低可锻铸铁第一阶段石墨化温度的研究

AN INVESTIGATION ON DECREASING TEMPERATURE OF THE FIRST STAGE GRAPHITIZATION FOR MALLEABLE IRON ANNEALING

在国内外近年来可锻铸铁孕育剂研究的基础上，研制出一种能在８００℃以下使共晶渗碳体迅速分解的可锻铸铁用高效孕育剂，其成分为０．４％～０．５％ＦｅＳｉＢａ５ＲＥ３＋０．１％ＮａＣｌ十０．０１％～０．０１３％Ｂｉ．用该复合孕育剂处理的可锻铸铁，在８００℃以下保温２０～３０ｈ，即可完全石墨化，机械性能可达到或超过ＫＴＨ３５０－１０．从而可取消传统的可锻铸铁退火必须经过９００℃以上高温保温的第一阶段石墨化．因此可大大降低退火能耗，减少退火箱的烧损，消除铸件的变形、过热和过烧．既降低生产成本，又提高铸件质量．此外，还讨论了此孕育剂对可锻铸铁的孕育机理．

Based on the studies of the inoculants used for malleable iron in the present age,a new kind of high efficient complex inoculant consisting of 0. 4 %-0. 5 %FeSiBa5RE3+0. 1.%NaCl+0.01%￣0.013%Bi, which can promote the eutectic cementite decomposed rapidly below 800℃,has been developed. The as-cast which iron specimens inoculated by this noculant can be annealed completely under 800℃×20h, 720℃×5h or 780℃×24h, 720℃×5h. Their mechanical properties are over KTH350-10. The inoculation mechanism of this complex inoculant is also discussed in this paper.