Effect of externally added TiO2 particles on microstructure and inclusions of medium and low carbon steel
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摘要: 使用HLLG1217型高温电阻炉对中低碳钢重熔后添加TiO2粒子,利用金相显微镜、场发射扫描电镜等设备对得到的试样进行组织、夹杂物形貌和成分分析。结果表明:添加TiO2粒子后组织由块状铁素体和珠光体转变为针状铁素体、少量块状铁素体和珠光体;球形夹杂物增多,长条形和不规则的夹杂物减少;夹杂物平均尺寸由0.29 μm变为3.06 μm,1 μm尺寸所占比例增多达到28.69%;添加前后复合夹杂物主要成分均为O-Al-Si-Ti-Mn,Ti元素含量由3.36%增多到6.53%,表明TiO2粒子加入后与原夹杂物重新聚合,形成复合夹杂物,并诱发晶内铁素体形核析出。Abstract: TiO2 particles was added into the medium and low carbon liquid steel remelted by aHLLG1217 type high temperature resistance furnace. The microstructure, inclusion morphology and composition analysis had been investigated by an automatic metallurgical microscope, field emission S-4800 scanning electron microscope and other equipment. The results show that after adding TiO2 particles, the microstructure changes from a large amount of massive ferrite and pearlite to a large amount of acicular ferrite, a small amount of massive ferrite and pearlite. Besides, more spherical inclusions appears and amount of elongated and irregular inclusions decreases. The average size of inclusions changes from 0.29 μm to 3.06 μm, and the proportion of inclusion with around 1 μm size increases to 28.69%. Main components of composite inclusions before and after addition are O-Al-Si-Ti-Mn, and the content of Ti element increases from 3.36% to 6.53%, which fully indicates that the TiO2 particles re-polymerizewith the original inclusions to form composite inclusions after adding, and induce acicular ferrite nucleation and precipitation.
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Key words:
- medium and low carbon steel /
- TiO2 particles /
- IGF /
- microstructure /
- inclusions
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表 1 样品2元素成分检测结果
Table 1. Chemical compositions of Sample 2
% C Mn S P Si Als Ti 0.13 1.55 0.004 0.005 0.31 0.07 0.03 表 2 Ti氧化物晶体结构信息
Table 2. Ti oxide crystal structure information
名称 空间结构 空间群 晶胞参数/nm 夹角/(°) a b c α β γ TiO 面心立方 Fm-3 4.175 4.175 4.175 90 90 90 Ti2O3 刚玉结构 R-3c 5.148 5.148 13.636 90 90 120 Ti3O5 黑钛石型结构 C12/m1 9.752 3.802 9.442 90 91.55 90 TiO2 金红石结构 P42/mnm 4.594 4.594 2.959 90 90 90 -
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