Inoculation refers to adding a small amount of other substances to the liquid metal during the solidification process to promote nucleation and inhibit growth, thereby achieving the purpose of grain refinement. Traditionally, adding additives to cast iron is called inoculation; adding additives to non-ferrous alloys is called modification. In essence, inoculation mainly affects nucleation and promotes grain freedom; while modification changes the growth mechanism of the crystal (inhibits growth), thereby affecting the crystal morphology.

        
        effect

The mechanical properties of grey cast iron depend largely on its microstructure. Grey cast iron that has not been inoculated has an unstable microstructure, poor mechanical properties, and is prone to white spots in thin-walled parts of the casting. Inoculation is essential to ensure the consistency of casting quality [1].

The amount of inoculant used in cast iron inoculation treatment is very small, which has little effect on the chemical composition of cast iron, but has a great impact on its microstructure, thus improving the mechanical properties of gray cast iron and also having a significant impact on its physical properties. Good inoculation treatment has the following effects:

◆Eliminate or reduce the tendency of white mouth;

◆Avoid supercooled tissue;

◆Reduce the wall thickness sensitivity of cast iron parts, so that the difference in microstructure and hardness between thin and thick sections of castings is small;

◆It is conducive to the nucleation of eutectic clusters, increasing the number of eutectic clusters;

◆ Make the graphite in cast iron mainly small and evenly distributed A-type graphite, thereby improving the mechanical properties of cast iron.

Well-inoculated cast iron has better fluidity, reduced shrinkage of castings, improved processing performance, and reduced residual stress.

Inculation treatment refers to the addition of a small amount of other substances to the liquid metal during the solidification process to promote nucleation, inhibit growth, and achieve the purpose of refining grains. Traditionally, adding additives to cast iron is called inoculation; The addition of additives to non-ferrous alloys is called metamorphism. Essentially, inoculation treatment mainly affects nucleation and promotes grain dissociation; Metamorphic treatment is to change the growth mechanism of the crystal (inhibit growth), thereby affecting the morphology of the crystal.

function

The mechanical properties of gray cast iron are largely determined by its microstructure. Gray cast iron without inoculation treatment has unstable microstructure, low mechanical properties, and white mouth is easy to appear on the thin wall of the casting. In order to ensure the consistency of the quality of the casting, inoculation treatment is essential [1].

The inoculant used in the inoculation treatment of cast iron is very small, which has little effect on the chemical composition of cast iron, but has a great impact on its microstructure, so it can improve the mechanical properties of gray cast iron and has a significant impact on its physical properties. Good inoculation treatment has the following effects:

◆ Eliminate or alleviate the tendency of white mouth;

◆ Avoid supercooling tissues;

◆ Reduce the sensitivity of wall thickness of iron castings, so that the difference in microstructure between thin and thick sections of castings is small, and the difference in hardness is also small;

◆It is conducive to the nucleation of eutectic clusters and increases the number of eutectic clusters;

◆ The form of graphite in cast iron is mainly fine and evenly distributed A-type graphite, so as to improve the mechanical properties of cast iron.

Shaanxi Keke Metal Materials Co., Ltd.

Shaan Xi Ke Mu Metal Materials ,.CO LTD

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