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What will happen if the cast iron is inoculated excessively

Update time:2022-06-16 Focus on:1381

Inoculants have great applications and functions in the field of cast iron. There are many kinds of inoculants, more than 300 kinds. According to their scope of application, they can be roughly divided into four categories: inoculants for cast iron and inoculants for cast ductile iron. , Inoculant for ductile iron, inoculant for vermicular cast iron, etc.

Inoculation can promote the graphitization of cast iron, improve the shape distribution and size of graphite, reduce the tendency of white mouth, and improve the strength. But if it is over-fertilized, it will not achieve the desired effect.

A reasonable amount of inoculation depends on whether the number of eutectic clusters is too small or too much under the metallographic phase. If the inoculation of ductile iron is too much, the number of eutectic clusters will increase and the tendency of loosening will increase, that is why pressure-bearing parts pay attention to inoculation. The reason for the amount of hypereutectic ductile iron is too large, and the graphite will float.

Excessive inoculation will lead to high silicon content, and silicon brittleness will occur if the amount exceeds a certain amount, and the final silicon content will lead to the thickening of A-type graphite; shrinkage cavities and porosity will also be easily generated, and the amount of F in the matrix will increase; there will also be less pearlite. , there is more ferrite, but it reduces its strength.

If the inoculation amount is too large, the expansion of the cast iron during the solidification process will be reduced, the graphite precipitation will be reduced, the liquid shrinkage will become larger, and the increase of the eutectic group will cause poor feeding, resulting in the generation of shrinkage porosity.

To learn more about the inoculant, please visit the official website of Heritage Casting: