抄録
Although there have been many procedures developed for the dissolution of iron matrix in order to separate non-metallic residues from steel samples, they are all so tedious and time-consuming, because they all require strictly neutral atmosphere and their reactions are so weak that they need long time to dissolve samples. Moreover the residues separated are more or less mixtures of oxides, nitrides, sulfides, and possibly of other non-metallic constituents; nevertheless they are expressed as oxides of silicon, aluminum, manganese, and iron, after a mere elementary analysis. Hence they can be considered very accurate for the purpose of separation neither of oxides only nor of combined total non-metallic inclusions. The author proposes a simple and rapid dissolution procedure for the separation of non-metallic inclusions of plain carbon steel containing less than 0.5% carbon with a ten per cent methanolic bromine solution at room temperature. The applicability of this new procedure is studied in comparison with the methanolic iodine procedure, which is considered one of the best procedures hitherto developed. The bromine method is simple because it can be carried out in an ordinary atmosphere, and is rapid because the solution used is strong enough, and besides it is more accurate for separation of oxide inclusions because it can dissole away nitrides of iron and manganese and sulfide of iron at ordinary temperature together with the matrix, all of which are insoluble by iodine method even at 60°C. The reaction equivalence, as one of the preliminary experiments, was also studied and it was found that the iron matrix is brought into solution FeBr2 independent of the concentration of bromine in methanol within the range of 2.5 to 10 vol-%.
