Experimental Study of a Representative Sample to Determine the Chemical Composition of Cast Iron

In metallurgical practice, the material is considered of adequate quality if it meets the customer’s expectations. It is necessary to take representative samples and perform quality testing to avoid financial and intangible losses. Sample contamination and matrix and surface quality play a significant role in the accuracy of chemical analyses. The purpose of this paper is to point out the advantages of specific methods of taking samples, such as immersion and spoon sampling of molten metal, and, in the experimental part, to assess the impacts of factors affecting the quality of the sampling. The influence of time of final sampling on determining the true amount of magnesium during a single melt and the influence of duration of mixing of molten cast iron on the accuracy of chemical analysis of the control sample were investigated. It is important that the time between the modification and casting of the liquid cast iron from the casting ladle be as short as possible. This is because the magnesium burns out and thus the chemical analysis of the sample taken is not accurate. Another important factor is ensuring the melt before sampling is homogenized and has the minimum prescribed temperature (1420 °C). Increasing sample collection time will cause changes in its chemical composition.