The types

sizes

distributions and morphological changes of inclusions in magnesium treated ( 0. 0006% Mg ) and calcium treated (0. 0010% Ca) 0.45% C steel are compared and analyzed by optical microscopy

scanning electron microscopy and in-situ electrolysis in non-aqueous solution. The results show that compared with the traditional calcium treatment process

after adding a certain amount of magnesium to 0.45% C steel

the Al

2

O

3

in steel is transformed into fine and dispersed MgO • Al

2

O

3

and MnS takes MgO • Al

2

O

3

as nucleation particles at the end of solidification to form MnS- MgO • Al

2

O

3

composite inclusions with soft outside and hard inside. The inclusions with this structure are not easy to deform

and can still keep spheric

al or spindle shape during rolling

which can improve the ratings of A-type sulfide and B-type alumina; The inclusions in steel are more dispersed and distributed

the proportion of small-sized inclusions in steel with 0 ~ 4μm2 increases

and the morphology of inclusions in steel is improved which is more conducive to improving the properties of steel.