75 Ferrosilicon inoculant is a kind of inoculant that can promote graphitization, reduce whitening tendency, improve graphite morphology and distribution, increase the number of eutectic groups, and refine the matrix structure. It has a good effect in a short time after inoculation treatment. It is mainly suitable for general or post-instantaneous pregnancy in various situations.
In the production of ductile iron, inoculation is an essential process due to the relatively large tendency of supercooling. The main function of using 75 ferrosilicon inoculant for inoculation treatment is to increase the number of graphite nodules in ductile iron, improve its roundness, refine graphite nodules, prevent nodularization recession, reduce the tendency of white mouth, and prevent the formation of eutectic clusters Between the formation of free cementite and segregation. The most important thing is that adding inoculants can increase the number of graphite cores in the solidification process of ductile iron, and then increase the number of eutectic clusters to improve the mechanical properties of ductile iron.
The inoculant commonly used in the production of ductile iron in China is ferrosilicon. The content of Ca and Al which play an important role in inoculation in this ferrosilicon is not specifically limited, which makes the inoculation effect very unstable and makes the produced nodular cast iron Components often form various organizational deficiencies. After the 1990s, on the basis of the introduction of foreign technology, the research and application of China’s domestic inoculants have made great progress, and the development of strontium-containing ferrosilicon inoculants, rare earth inoculants, silicon barium inoculants, etc. has greatly improved The types and application ranges of cast iron inoculants are enriched.
Practice shows that the current series of inoculants in China can basically meet the needs of the development of iron castings production. However, the amount of ferrosilicon inoculants still accounts for more than 80% of the total amount of cast iron inoculants, resulting in very unstable inoculation effects and often scrapped castings. Therefore, the development of 75 ferrosilicon inoculants plays a vital role in improving the quality of iron castings, and the ability to produce qualified inoculant products that meet the requirements has become a crucial factor restricting the development of the iron casting industry.