Area method analysis and thermodynamic behavior of nonmetallic micro-inclusions in casting slab of GCr15 bearing steel

Abstract

The distribution and characteristics of nonmetallic micro-inclusions of GCr15 bearing steel were explored through metallographic area method in virtue of tracer method and electronic microscope. The results show that the micro-inclusions, of which the average value is 0.032%, are mainly the compounds formed via the adsorption/aggregation of multielement deoxidized compounds and secondarily deoxidized products on tundish liquid level. The micro-inclusions of diameters from 0 to 5 μm are 92.5% in total, which basically determines the characteristics of inclusions distribution in casting slab. The inclusions of diameters more than 10 μm only account for less than 1% in total, which have little influence on steel quality. The relationship between equilibrium compositions of the first deoxidation products and molten steel compositions was also calculated based on thermodynamic theory.

Keywords

nonmetallic micro-inclusions / GCr15 / area method / tracer method / chemical equilibrium

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