High-strength gray iron casting smelting method

Abstract

The invention discloses a high-strength gray iron casting smelting method. Gray iron casting smelting is performed with scrap steel, pig iron and foundary returns as raw materials. The smelting method includes the specific steps that ferromanganese and the 10% pig iron are added into a medium-frequency induction electric furnace; then, carbon agents and the scrap steel are added at the same time; smelting is performed till the size of molten iron in the induction electric furnace is reduced by 3 / 4 through smelting; smelting is performed while silicon carbide is added, so that base iron is formed; the base iron is heated so that temperature can be raised; the induction electric furnace is adjusted to be in a heat-preservation state, and standing lasts for 5-10 minutes; and silicon and zirconium inoculant and final molten iron are punched into iron discharging ladles, and then the silicon and zirconium inoculant and the final molten iron are punched into a cast cavity so that casting can be performed. The method replaces a traditional method that alloyed elements such as copper or tin need to be added, manufacturing cost is reduced, and the foundary returns can be conveniently managed. The method that the silicon carbide and furnace burden are smelted at the same time is adopted for pre-processing the molten iron, and the pre-processing effect is guaranteed. The efficient silicon and zirconium inoculant is adopted so that the inoculation effect is guaranteed, and more than 80% of A-type graphite is obtained from the casting body metallographic phase.

Description

technical field [0001] The invention relates to a method for smelting gray iron castings, in particular to a method for smelting high-strength gray iron castings, and belongs to the field of chemical smelting. Background technique [0002] Gray cast iron is basically a eutectic alloy composed of iron, carbon and silicon, in which carbon mainly exists in the form of graphite. Controlling the morphology and matrix metal structure of the graphite formed when cast iron solidifies is critical to producing quality castings. Inoculation treatment is one of the most important links in the production process. A good inoculation treatment can make the gray cast iron have a satisfactory microstructure, so as to ensure the mechanical properties and processing properties of the casting. Adding an inoculant to liquid cast iron can form a large number of submicroscopic cores and promote the formation of eutectic clusters in the liquid phase. When approaching the eutectic solidification ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a smelting method for high-strength gray iron castings, to solve the above-mentioned difficult problem of high manufacturing cost, and to obtain A-type graphite with a higher yield