Melt sampling for hydrogen analysis optimized with the help of computer simulation

Abstract

This research was carried out in laboratory conditions on a semi-continuous ingot casting machine owned by the Siberian Federal University. The paper compares the results of computer simulation carried out for AK12 alloy solidification process in the PoligonSoft programme. A new original mould is described designed for sampling liquid aluminium and its alloys for hydrogen analysis. The new mould has a larger surface area and walls that are made in the form of a heat exchanger intended for more efficient heat removal. It is shown that, in the commonly used Rensley mould, the melt solidifies in 14 seconds at the metal crystallization rate in the range from the pouring temperature to the solidus temperature of 15 oC/s, while in the case of the new mould these parameters are 12 seconds and 17.5 oC/s, correspondingly. The paper also compares the results of dissolved hydrogen analysis obtained when sampling was done with both the conventional Rensley mould and the new one. It was found that the concentration of hydrogen in the samples taken with the Rensley mould is lower on average by 0.01 cm3/100 g Al than in the samples taken with the new mould. Based on the results of the study, a conclusion was drawn that the proposed mould design delivers an additional advantage when sampling liquid metal. It also helps determine the concentration of dissolved hydrogen in molten aluminium with a higher degree of accuracy.This research was carried out by the Siberian Federal University as part of the governmental assignment for research; Project No. FSRZ-2020-0013.