rare earth ferro silicon magnesium

Nodulizer is one key raw material for producing nodular cast iron, its quality directly affects the quality of nodular cast iron,such as the spheroidizing rate of the casting, the size of the graphite ball, and the tendency of the casting to produce shrinkage, porosity and slag inclusion, etc. At present the commonly used nodulizer is rare earth ferro silicon magnesium,it contains the elements of magnesium, rare earth,calcium and certain iron, silicon and a small amount of manganese, aluminum, titanium, etc. Magnesium is considered to be the best and most important spheroidizing element,rare earth elements can be also used for spheroidizing, but the ability is second than magnesium.

Most of producer of the nodular cast iron abroad uses arc smelting and adopts a desulfurization process, which mainly uses low magnesium (2.5%~6%) and low RE (less than 2%) rare earth ferro silicon magnesium spheroidizing agents. The spheroidizing reaction is stable and the roundness of graphite spheres is relatively high.

Rare earth is divided into light rare earth and heavy rare earth. The China domestic production of ordinary nodular cast iron is mainly composed of lanthanum and cerium etc light rare earth nodulizer. Along with the research of heavy rare earth, it has been used in thick section nodular cast iron, and with good effect, it can effectively overcome the problems of thick spheroidal graphite cast iron castings that are prone to spheroidization recession, strong cross-section sensitivity and low mechanical properties at the center of the cross-section.

The calcium is generally a limited element in the rare earth ferro silicon magnesium nodulizer, usually 2%-3% for electric furnaces, it can control the absorption and reaction speed of the nodulizer in the molten iron, but excessive calcium can not only make slowly melts of the nodulizer but also lead to the development of graphite to be worm shape, especially to the large-section ductile iron. Therefore, in the production of large-section ductile iron, we must pay attention to control of calcium in the nodulzier. There is a intuitive reaction of low calcium which appear less slag in the ladle after spheroidization.

Ferro and silicon are the basic components in the rare earth ferro silicon magnesium, and they are compounded when smelting alloys. Changing their content can adjust the density and melting pointing of nodulizer. The silicon is generally 40%-50% in rare earth ferro silicon magnesium nodulizer, the melting point is 1220℃, low silicon and high ferro means the melting point higher and density bigger, if the silicon is too low, the nodulizer is difficult to dissolve, and the magnesium loss is large, content of MgO maybe more.

Anyang Huatuo Metallurgy told you that the high quality rare earth ferro silicon magnesium nodulizer must have stable chemical composition, small fluctuations, high alloy purity, low magnesium oxide content, dense alloy structure, no air shrinkage, and uniform and reasonable particle size distribution, if any need welcome for contact.