The characteristics and control of Ds inclusions in rail transit steel
In order to effectively control the harm of inclusions in steel for rail transit,the characteris-tics of Ds inclusions are analyzed by means of scanning electron microscopy and energy spectrum analy-sis.The shape of inclusions in steel is typical spherical.The composition of inclusions is mainly cal-cium aluminate with wrapping layer of CaS inclusions,and the size is about 206 μm.The analysis of process technical indicators shows that Ds inclusions is caused by insufficient time of removal of inclu-sions during calcium treatment process and the low yielding rat of Alt during RH vacuum degassing process.Some optimizations and improvements are carried out from the aspects of calcium treatment process and RH process.The corresponding effects are achieved.The effective control of Ds inclusions in the steel is realized.