The results of studies on the use of magnesium alloy in modern Tundish for production of vermicular graphite cast irons were described. This paper describes the results of using a low-magnesium ferrosilicon alloy for the production of vermicular graphite cast irons. The paper presents a vermicular (and nodular) graphite in different walled castings. The results of trials have shown that the magnesium Tundish process can produce high quality vermicular graphite irons under the specific industrial conditions of Foundries - Odlewnie Polskie S.A. in Starachowice. In this work describes too preliminary studies on the oxygen state in cast iron and their effect on graphite crystallization.

The modification is a widespread method of improving the strength properties of cast iron. The impact in terms of increasing amounts of

eutectic grains has been thoroughly studied while the issue of the impact on the mechanical properties of primary austenite grains has not

been studied in depth yet. The paper presents the study of both aspects. The methodology was to conduct the melting cast iron with flake

graphite, then modifying the alloy by two sets of modifiers: the commercial modifier, and a mixture of iron powder with a commercial

inoculant. The DAAS test was carried out to identify the primary austenite grains. The degree of supercooling was determined and the

UTS test was performed as well. Additionally carried out the metallographic specimen allowing for counting grains. It can be concluded

that the introduction of the iron powder significantly improved the number of austenite primary grains which resulted in an increase

in tensile strength UTS.