Formation mechanism and industrial control of Ds inclusions in high carbon grinding ball steel
Ds non-metallic inclusions have large size and poor ductility,which seriously affect the fatigue life and oth-er key performance indicators of TL-1D grinding ball steel.The whole process sampling analysis of TL-1D grinding ball steel in an enterprise showed that the Ds non-metallic inclusions of this steel grade exceeded the standard.The main Ds non-metallic inclusions in this steel grade were Al2O3-CaO-MgO-CaS,which appeared greatly after LF re-fined calcium treatment.The formation mechanism of Ds non-metallic inclusions was summarized.Firstly,Al2O3 as the core began to nucleate,then it combined with[Mg]and[Ca]in the molten steel and grew up to form CaO-Al2O3-MgO spherical inclusions.Finally,the outer layer of spherical inclusions and CaS formed Al2O3-CaO-MgO-CaS outer envelope.The results of industrial tests confirm that calcium treatment is not conducive to the control of Ds non-metallic inclusions in TL-1D steel,resulting in an increase in the size of inclusions.Then the production process scheme of non-calcium treatment in the refining process of TL-1D grinding ball steel production was pro-posed.The test results show that the calcium content in the molten steel is in a saturated state,and the optimized refining slag composition tends to liquid zone,which improves the soft melt adsorption performance of the refining slag system on inclusions in the refining process,improves the adsorption removal rate of Ds non-metallic inclusions when they float to the slag layer,and finally the initial inspection pass rate of continuous casting billet increases from 95.4％to 97.0％.The research results have reference value for the industrial production of grinding ball steel.
grinding ball steelnon-metallic inclusioncleanlinessnon-calcium treatmentindustrial test
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