In-mold inoculation insert for thick-transect nodular iron castings and preparation method thereof

Abstract

The invention provides an in-mold inoculation insert for thick-transect nodular iron castings, which is prepared from the following components in percentage by weight: 75-80% of silicon iron, 2% of silicon-calcium alloy, 5% of rare-earth magnesium silicon iron, 3% of aluminum-iron alloy, 5% of manganese-iron alloy and 5-10% of steel scrap. The preparation method comprises the following steps: weighing the components according to the percentage by weight; adding the steel scrap and manganese-iron alloy into an acidic intermediate frequency furnace, vertically inserting a graphitic carbon bar in the middle, adding the silicon iron, and heating to 1500-1550 DEG C to melt down the substances in the furnace; deslagging the liquid in the furnace, adding the aluminum-iron alloy, and melting into an iron liquid; preheating a casting ladle to 50-100 DEG C, adding the silicon-calcium alloy and rare-earth magnesium silicon iron, pouring the iron liquid into the casting ladle, and melting into the final iron liquid; and carrying out mold casting on the final iron liquid, and forming to obtain the in-mold inoculation insert. The weight of the in-mold inoculation insert can reach 2kg or so; and the in-mold inoculation insert has the advantages of low melting point, short melting time and favorable inoculation effect.

Description

technical field [0001] The invention relates to the technical field of metal material preparation, in particular to an inoculum block for thick and large section ductile iron castings and a preparation method thereof. Background technique [0002] Ductile cast iron is a high-strength cast iron material developed in the 1950s. The main production process is to obtain spherical graphite through spheroidization and inoculation treatment, so as to effectively improve the mechanical properties of cast iron, especially to improve plasticity and toughness, so as to obtain Higher strength than carbon steel. Because its comprehensive performance is close to that of steel, it has been successfully used to cast some parts with complex stress, high strength, toughness and wear resistance. [0003] Thick and large section ductile iron refers to ductile iron with a wall thickness ≥ 100mm. The inoculation and spheroidization of thick and large section ductile iron are very critical. The b...

AI Technical Summary

Problems solved by technology

[0005] The production of casting inoculation blocks is mostly green sand casting, which is prone to defects such as pores and sand sticking on the surface, and because of the high resistance of 75 ferrosilicon, it is difficult to generate eddy currents in the furnace and difficult to melt, which increases the difficulty for mass and rapid production

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