Abstract
A study is made on preparation of cast iron samples which show various microstructures in order to determine the silicon and manganese contents by the emission spectrographic analysis.The chipped sample (approximately 10-15 gr.) is packed into a quartz crucible together with tin shot and is melted in a high frequency induction furnace with a flow of argon at the rate of 100 to 200 ml per minute.It is sufficient for restraining the graphitization to add 5 or 8 per cent of tin into a hypo-eutectic or a hyper-eutectic cast iron, respectively.It takes about 7 minutes to prepare a sample by this re-melting method.
Precision of measurement of manganese in samples is 4 to 11 per cent without tin, while it is 2 per cent in the case that tin is added in samples.As the coefficient of variation for silicon, however, is much larger than that of manganese, it is thought that more studies must be made on the state of silicon in samples.
Generally speaking, the appearance of ledebulite and pearlite decreases the iron line intensity and that of ferrite tends to the increase of intensity.In white cast iron, the co-existence of tin increases the iron, silicon and manganes line intensities because tin promotes the excitation and emission. Reversely, the iron intensity of grey cast iron decreases by an addition of tin and the result attributes to the increase of pearlite in samples.
Similarly as for the spectral intensity of component elements, it is considered that the formation of compounds such as carbide affects on the intensity.
