Instant inoculation method of large-section magnesium iron

Abstract

The invention relates to an inoculation method for large-section ductile iron, which can accurately change the adding speed of inoculant according to different flow rates of molten iron during pouring. The method can be used for producing the large-section ductile iron with high performance requirement and capable of resisting low-temperature shock. The inoculation method for the large-section ductile iron is characterized in that the molten iron is poured into a straight pouring channel from a runner box, an automatic feeding device adds the inoculant into the straight pouring channel through a pipeline at the same time of pouring, the inoculant and the molten iron are in a half filling state in the straight pouring channel, mixed and then poured into a die cavity, and the automatic feeding device automatically adjusts the adding speed of the inoculant according to the flow change of the molten iron.

Description

technical field [0001] The invention relates to an instantaneous inoculation method, in particular to an instantaneous inoculation method for pouring large-section ductile iron by using a sprue box. Background technique [0002] In the production process of large-section ductile iron, the most prominent problems are spheroidization and inoculation recession, which lead to fragmented graphite or graphite distortion, and deteriorate the performance of castings, so inoculation treatment is extremely important. The inoculation treatment can determine the size of the ball diameter, the number of graphite balls, the roundness of the graphite balls, and even the key factors to inhibit the decline of the balls. Obtaining a high-grade inoculant effect is not only related to the composition and amount of the inoculant, but also closely related to the time and method of adding the inoculant. Usually, the closer the inoculation treatment is to the solidification time of molten iron, th...

AI Technical Summary

Problems solved by technology

But the problem with this method is that the inoculant can only enter the cavity after it is completely dissolved in the sprue box. Preservation, cannot quickly enter the cavity and cool down rapidly with the casting body, so it is easy to reduce the nodulizer rate, inoculation recession, graphite distortion, and fragmented graphite, which in turn leads to a reduction in the nodularization rate, making the mechanical properties of the casting The performance does not meet the technical standard requirements

[0004] There are many kinds of inoculants currently used: 75SiFe, Si-Ba, Si-Sr, Si-Zr, etc., but for large-section ductile iron, none of them can achieve a satisfactory spheroidizing effect, and graphite distortion or even Fragmented graphite, the spheroidization rate is low, which leads to the mechanical properties of the castings not meeting the standard requirements

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