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In this study, the distribution and enrichment characters of heavy metals were explored. And the potential ecological risk levels of heavy metals were evaluated by geo-accumulation index method and potential ecological risk index method. The concentrations of heavy metals in sediments of Harbin section of Songhua River are: Zn>Pb>Cr>Cu>Ni>Cd. The enrichment degree of Zn is the highest, while Cd is the lowest. The potential ecological risk indexes of heavy metals in the sediments of section of Songhua River in Harbin are: Cd>Pb>Cu>Zn>Ni>Cr. The main heavy metals pollution is Cd, which has low content but considerable potential ecological risk and contributes most to RI. The ecological risk level of heavy metals in the sediments of the section of Songhua River in Harbin is moderate.

The effect of magnesium on the morphology and composition of the carbide in annealed bearing steel was studied. The morphology of carbide was observed and statistical analysis was carried out. The results showed that the non-uniform distribution of carbides in bearing steel was obviously improved with increasing the content of magnesium. Segregation thermodynamics indicated that the segregation of magnesium to grain boundaries prevented element such as Cr, C from enriching on grain boundary, which was helpful for the reduction of network carbide precipitation. The chemical analysis results proved this viewpoint.

Various Ti oxides formation potential was analysised by thermodynamics during solidification of steel. It was found that Ti3O5 is the most stable one among all the types of Ti oxides. The effect of Mn element on the structure of Ti oxide was analysised by some experiments. The structure of Ti oxide without Mn is Ti3O5, and the inclusion, which contains some content of Mn, is Ti2O3 with rhombohedra structure. It is assumed that, [Ti] and [O] in liquid steel precipitated in form of Ti3O5. During the cooling process of solid steel, Ti3O5 reacted with [Mn], and exsited in form of Ti2O3 and MnO complex inclusion, which is advantageous for the nucleation of IGF.

It will be no damage for small non-metallic inclusions by non-aqueous electrolytic technique. However, there are some unsolved problems: the interference of by-product, the corrosion of small inclusions and the low efficiency. PH value, colloid and electrolytic efficiency were discussed in this paper to optimizing electrolysis parameters. Finally, ultrafine non-metallic inclusions were extracted successfully with high efficiency. The results showed that complex oxides and sulfides were kept well and the contents of by-product were reduced distinctly. Three dimensional morphology inclusions were observed with clear background.