Based on the self-designed bifilar electroslag remelting furnace with mould rotation, the effect of mould rotation speed on cleanliness of electroslag ingot for M2 high speed tool steel was studied in detail by ASPEX automatic inclusion analyzer. It was found that the inclusions in the ESR (Electroslag Remelting) ingot were mainly composed of Al2O3, Al2O3–MnS, Al2O3–SiO2–CaO–MnS, MgO–Al2O3–SiO2–CaO–MnO, MgO–Al2O3–SiO2–CaO–TiO2–MnS and Al2O3–SiO2–CaO–MnO–TiO2. Among them, Al2O3, Al2O3–SiO2–CaO–MnO–TiO2 and Al2O3–MnS accounted for the largest proportion. During ESR with the stationary mould, there were more inclusions in steel and the diameter of the largest inclusion exceeded 50 μm. When the mould rotation speed was 6 and 13 r/min respectively, the number of inclusions, especially large inclusions, were greatly reduced. However, when the mould rotation speed increased to 19 r/min, the number and size of inclusions increased further, and the total oxygen and nitrogen content in the steel increased too. The main reason for the removal of large inclusions in ESR ingots was that the melting layer at the end of metal consumable electrode became thinner and the size of droplets became smaller due to the rotation of mould, and the contact area between slag and molten metal increased, which promoted the removal of inclusions. However, the excessive mould rotation increased the oxidation of consumable electrode and reduced the contact time between slag and molten metal, thus reducing the refining capacity of the ESR process.
Lizhong CHANG Kaihua CHANG Xiongming ZHU Jiashun CHEN Gang GAO
. Effect of mould rotation on inclusions in ESR ingot[J]. The Chinese Journal of Process Engineering, 2019
, 19(6)
: 1186
-1196
.
DOI: 10.12034/j.issn.1009-606X.219140
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