50Cr5MoV钢中非金属夹杂物行为

Behavior of non- metallic inclusion in 50Cr5MoV

对采用“EBT→LF→VD”工艺路线生产50Cr5MoV 锻钢轧辊炼钢过程全氧和夹杂物进行了分析．结果表明：LF精炼后钢液中ω（T[O]）平均为47×10^－6，VD 出站为14×10^－6，中间包为15．5×10^－6，铸坯为18×10^－6．LF 精炼初期，钢中夹杂物主要是不规则的 Al2 O3夹杂，96．75％的夹杂物尺寸小于10μm．LF 精炼后，大量夹杂物为 CaO －Al2 O3－SiO 为主要成分的0～10μm 复合氧化物夹杂．钢水向中间包转移过程中保护性浇注不理想，二次氧化严重导致钢水夹杂逐渐增多，主要为球形 mCaO·nAl2 O3的复合夹杂物．铸坯中99．81％的夹杂物尺寸小于10μm，其中大部分为球形钙铝酸盐夹杂，还有少量球状硅铝酸钙复合夹杂．全过程的工艺优化是控制夹杂物（主要是氧化物）的合理途径，可确保实现50Cr5MoV 合金铸钢的冶炼．

The total amount of oxygen content and inclusions in 50Cr5MoV forged steel roll by the route of EBT→LF→VD were analyzed .The results show the average ω（T[O]）is 47 ×10 -6 after LF refining and 14 × 10 -6 after VD refining ,and 15.5 ×10 -6 in tundish and 18 ×10 -6 in billet on average.During the initial stage of LF refining,the inclusions in steel mainly are irregular forms of Al2 O3 ,96.75% of the inclusions have diameters less than 10 μm.After the LF refining,most of the inclusions are 0 ~10 μm diameters of compound oxide inclusions,predominantly containing CaO-Al2 O3-SiO2 .During the transfer of steel to tundish,the protective casting is not ideal,and the severe reoxidation contributes to the growing amount of inclusions,mainly containing spherical mCaO·nAl2 O3 compound oxide inclusions.99.81 percent of the inclusions in the steel slab are less than 10 μm.Most of them are spherical calcium -aluminate compound inclusion,with a few spherical calcium aluminosilicate compound inclusion.Therefore,inclusion control in 50Cr5MoV steel is a systematic engineering and could not be achieved by partial technical improvement.