厚大断面RE-Mg球铁喷粉净化及球化效果的研究

利用自行研制的喷粉装置，首先探讨了厚大断面RE-Mg球铁喷粉脱硫净化的效果，然后研究了稀土镁球化剂在喷粉处理时的净化及球化效果，进而对喷粉脱硫、球化、孕育综合处理工艺进行了试验研究。结果表明：喷粉处理时活性CaO的脱硫率与CaC2的脱硫率相近，使得CaO取代CaC2成为可能，喷粉处理具有突出的净化作用，在脱硫的同时，使氧含量显著降低，同时使硫趋于均匀分布；喷粉球化是一种有效的新球化方法，可获得低硫、低氧、石墨圆整而细小的铸态铁素体球墨铸铁；综合喷粉球化工艺可将脱硫剂、球化剂、孕育剂同时喷入铁液，完成脱硫、球化、孕育过程，获得的球铁在强度较高的同时，使伸长率和冲击值也增大。

Study of Purification and Spheroidization of Heavy Section RE-Mg Ductile Iron in Powder Injection Process

The desulphurization of heavy section RE-Mg ductile iron in powder injection treatment is firstly studied utilizing a self-developed injection device, then the purification and spheroidization of RE-Mg nodularizer are studied, further experiments on the spheroidization of comprehensive process of desulphurization, spheroidization and inoculation are carried out. The results show that the desulphurization of active calcium oxide is similar to that of calcium carbide during powder injection treatment process, and thus makes it possible for calcium oxide to replace calcium carbide. Powder injection treatment has prominent purification, and the content of oxygen decreases significantly while desulphurizing. Meanwhile, the sulfur tends to be distributed more uniformly. Powder injection spheroidization is a new effective method of nodulizing which can produce cast ferrite ductile iron with low sulphur, low oxygen and finer rounded graphite. The comprehensive injection-spheroidization technique can achieve the desulphurization, spheroidization and inoculation while the desulfurizer, nodularizer and inoculant are injected into molten iron simultaneously. The ductile iron obtained has very high elongation and toughness in addition to higher tensile strength.