A spheroidizing process of pure magnesium for lost foam nodular cast iron

Abstract

The invention discloses a pure magnesium spheroidizing technology of lost foam ductile cast iron. The pure magnesium spheroidizing technology comprises the steps that a spheroidizing agent is placed into a lip-pour ladle reaction chamber, a cover of the reaction chamber is closed, and a conventional nucleating agent, ferrosilicon, is added into a lip-pour ladle; after molten iron in a heat-insulated furnace is subjected to deslagging, molten iron is added into the lip-pour ladle, and the temperature of molten iron is controlled to be 1520 DEG C to 1560 DEG C; then, the lip-pour ladle is overturned, and molten iron and the spheroidizing agent react for 60 s to 70 s; and pouring is carried out while stream inoculation is achieved, wherein the addition amount of the stream nucleating agent is 0.08% to 0.15% of the weight of molten iron; the spheroidizing agent is a mixture of pure magnesium ingots and calcium chloride; and the weight ratio of molten iron to the pure magnesium ingots to calcium chloride to ferrosilicon is 1000 to (1.4 to 2.0) to (0.2 to 0.5) to (4 to 8). According to the pure magnesium spheroidizing technology of lost foam ductile cast iron, the spheroidizing problem of high-sulfur high-silicon molten iron can be effectively solved, the spheroidizing grade is high, a required matrix structure can be obtained, the problems that the spheroidizing effect is poor, the quality of castings is not stable, and the rejection rate is high are solved, the technology does not require lip-pour ladle nucleating, the procedures can be decreased, and the labor intensity is reduced.

Description

technical field [0001] The invention relates to the technical field of casting technology, in particular to a process for spheroidizing pure magnesium of lost foam nodular cast iron. Background technique [0002] Since the successful production of nodular cast iron in the 1950s, the nodular cast iron industry has made great progress in China. Due to its high strength, high toughness and low price, nodular cast iron occupies an important position in the material market. The production process of nodular cast iron includes the following links: smelting qualified molten iron, spheroidizing treatment, inoculation treatment, furnace inspection, pouring castings, casting cleaning, etc.; and spheroidizing treatment is the core technology of the smelting process. Badness directly determines the performance of castings. There has been a lot of research in recent years. Commonly used methods include flushing method, wire feeding method, blowing method, bell jar method, pressure method...

AI Technical Summary

Problems solved by technology

[0005] The object of the present invention is to provide a pure magnesium spheroidization process of lost foam nodular cast iron, through which the pure magnesium spheroidization process of lost foam nodular cast iron can effectively solve the problem of spheroidization treatment of high-sulfur and high-silicon iron liquid, the spheroidization level is high, and The required matrix structure can be obtained, so as to solve the problems of poor spheroidization, unstable casting quality and high scrap rate. At the same time, the process does not need to be inoculated, which can reduce the process and reduce labor intensity.

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