Environment-friendly composite spheroidizing agent applied to thick and big ductile iron

Abstract

The invention relates to an environment-friendly composite spheroidizing agent applied to thick and big ductile iron. The composite spheroidizing agent comprises, by weight, 78-90 parts of spheroidizing agents, 5-20 parts of melt-resisting agents, 1-5 parts of dreg removing agents, 2-8 parts of purifying agents, 1-6 parts of desulfurizing agents and 2-5 parts of nucleating agents. The spheroidizing agent has the advantages shown by rear earth and magnesium during spheroidizing, and overcomes the defects of the rear earth and the magnesium. The magnesium is a primary spheroidizing element according to its ratio in the composite spheroidizing agent, while the rare earth has a secondary assisted spheroidizing function. The composite spheroidizing agent has good effects in desulfurizing, deoxidizing, iron liquid purifying, interference element eliminating, eutectic point reducing and supercooling degree increasing, and has the following effects on the performance of the ductile iron: improving casting mobility, reducing temperature of iron liquid oxidation films, changing shrinkage characters of ductile iron, reducing shrinking and loosening, improving mechanical performance, refining graphite and improving abrasive resistance.

Description

technical field [0001] The invention belongs to the field of nodulizers, in particular to an environment-friendly composite nodulizer applied to thick ductile iron pieces. Background technique [0002] The commonly used nodulizers are metal magnesium and rare earth magnesium alloys. Metal magnesium was first used in the production of nodular cast iron, which has the advantages of good spheroidizing effect and low price. But the boiling point of metallic magnesium is 1108°C, which is about 350°C lower than the temperature of molten iron treatment. Because the gasification of magnesium makes the molten iron boil, the magnesium reacts with the oxygen in the air and burns to generate magnesium oxide, resulting in a low absorption rate of molten iron. Therefore, metal magnesium is used as a nodulizer, and it is generally used when the molten iron is subjected to a large external pressure to prevent the escape of magnesium vapor. The advantage of rare earth magnesium alloy is t...

AI Technical Summary

Problems solved by technology

The advantage of rare earth magnesium alloy is that the spheroidization method is simple and has the ability to resist interference elements, but it is prone to abnormal graphite, which affects the performance of nodular cast iron