Vermicularizing inoculation method of vermicular graphite cast iron

Abstract

The invention discloses a vermicularizing inoculation method of vermicular graphite cast iron. In the smelting process of molten iron in a medium-frequency furnace, a high-purity rare earth alloy is fed in the molten iron before tapping, and is fully dissolved through an electromagnetic stirring effect of the medium-frequency furnace for primary vermicularizing treatment; a vermicularizing sensitive area of the molten iron is enlarged to improve the vermicularizing success rate and the vermicularizing effect; then, a rare earth-contained inoculation alloy is fed in a ladle after tapping for secondary vermicularizing treatment; the quantity of residual rare earth is supplemented to improve the inoculation effect and prolong the fading time; and obtained qualified vermicular graphite cast iron liquid is used for pouring castings. The method effectively improves the vermicularizing success rate, widens the vermicularizing sensitive range, prolongs the inoculation fading time, increases the product pass percent, and in particular, is suitable for a casting process of vermicular graphite cast iron cylinder jackets of marine diesel engines.

Description

technical field [0001] The invention relates to a casting process method, in particular to a vermicular inoculation method for vermicular graphite cast iron for pouring blank castings of marine diesel engine cylinder liners, and belongs to the technical field of casting. Background technique [0002] The vermicular inoculation method refers to a processing method that uses a specific vermicular agent to make most of the graphite precipitate in the shape of vermicular and partly spherical during the solidification process of molten iron. The obtained material is called vermicular graphite cast iron. [0003] The mechanical properties of vermicular graphite cast iron are close to those of nodular cast iron, and it has good anti-vibration, heat conduction and casting properties comparable to gray cast iron. At the same time, it has better plasticity and fatigue resistance than gray cast iron. More importantly, vermicular graphite Cast iron has better wear resistance than gray c...

AI Technical Summary

Problems solved by technology

In the vermicular inoculation process, due to the narrow sensitive area of ​​vermicular graphite cast iron, different vermicular inoculation methods are likely to cause excessive vermicularization and poor conditions, resulting in spherical or flake graphite precipitation, which makes the material properties deteriorate sharply and is difficult to Meet the use requirements

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