从LF炉精炼脱硫热力学和动力学原理出发分析了影响脱硫的相关因素。对200 t LF炉超低硫钢生产实例的分析表明:当钢液初始硫含量(质量分数,下同)低于0.012%时,精炼终点硫含量可脱除至0.002%以下;1550~1600℃的钢液温度为LF炉精炼超低硫...从LF炉精炼脱硫热力学和动力学原理出发分析了影响脱硫的相关因素。对200 t LF炉超低硫钢生产实例的分析表明:当钢液初始硫含量(质量分数,下同)低于0.012%时,精炼终点硫含量可脱除至0.002%以下;1550~1600℃的钢液温度为LF炉精炼超低硫钢经济合理的冶炼温度;LF炉进站钢水酸溶铝含量为0.02%~0.05%,满足LF炉深脱硫要求;当精炼渣碱度为4.0左右时,LF炉脱硫效率最高;要获得大于80%的脱硫率,渣中(FeO)+(MnO)的含量需尽量控制在0.8%以下;从冶炼成本和钢水质量的角度考虑,最经济合理的LF炉精炼渣量为15~20 kg/t;LF炉底吹氩气量控制在0.10~0.18 Nm^(3)/t时可获得较好的脱硫效果。展开更多
B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting te...B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting temperature of two series of refining slags including the low basicity slags （the mass ratio of CaO/SiO2 is 3--4） and the high basicity slags （the mass ratio of CaO/SiO2 is 5--8.75） were investigated. The slag melting temperature was meas- ured using the hemisphere method. The results indicate that the fluxing action of B2O3 is better than that of CaF2 and A1203. For the CaO-based refining slag with low basicity, the melting temperature is decreased effectively when B2O3 is used to substitute for equal mass of CaF2, Al2O3 and SiO2, respectively. For the CaO-based refining slag with high basicity, when CaF2 is substituted by B2 03, the melting temperature can be decreased remarkably. Espe- cially, when the mass ratios of CaO/Al2O3 and CaO/SiO2 are in the range of 1.1--4.0 and 5.25--8. 0, respectively, the slag melting temperature is lower than 1 300 ℃. Therefore, the 132 03-containing refining slags with high ratios of CaO/Al2O3 and CaO/SiO2 have ultra low melting temperature.展开更多
Investigations were made both in laboratorial and industrial scales on formation of non-metallic inclusions with relatively lower melting temperatures to improve the fatigue property of the special steels which contai...Investigations were made both in laboratorial and industrial scales on formation of non-metallic inclusions with relatively lower melting temperatures to improve the fatigue property of the special steels which contained extra low oxygen.It was found in laboratory studies that steel/slag reaction time largely affected non-metallic inclusions in steel.With the slag/steel reaction time increasing from 30 to 90 min,inclusions of MgO-Al2O3 spinel were gradually changed into CaO-MgO-Al2O3 system inclusions which were surrounded by lower melting temperature softer CaO-Al2O3 surface layers.By using high basicity and as much as 41 mass% Al2O3 refining slag,the ratio of the lower melting temperature CaO-MgO-Al2O3 system inclusions was remarkably increased to above 80%.In the industrial experiments,it was found that the inclusions changed in the order of "Al2O3 →MgO-Al2O3 system→CaO-MgO-Al2O3 system" in the secondary refining,and the change from MgO-Al2O3 system to CaO-MgO-Al2O3 system took place from the outside to the inside.The diffusion of CaO and MgO inside the layer of CaO-MgO-Al2O3 was considered as the controlling step of the inclusion transfer.Through LF and RH refining,most inclusions could be transferred to lower melting temperature CaO-Al2O3 and CaO-MgO-Al2O3 system inclusions.展开更多
文摘从LF炉精炼脱硫热力学和动力学原理出发分析了影响脱硫的相关因素。对200 t LF炉超低硫钢生产实例的分析表明:当钢液初始硫含量(质量分数,下同)低于0.012%时,精炼终点硫含量可脱除至0.002%以下;1550~1600℃的钢液温度为LF炉精炼超低硫钢经济合理的冶炼温度;LF炉进站钢水酸溶铝含量为0.02%~0.05%,满足LF炉深脱硫要求;当精炼渣碱度为4.0左右时,LF炉脱硫效率最高;要获得大于80%的脱硫率,渣中(FeO)+(MnO)的含量需尽量控制在0.8%以下;从冶炼成本和钢水质量的角度考虑,最经济合理的LF炉精炼渣量为15~20 kg/t;LF炉底吹氩气量控制在0.10~0.18 Nm^(3)/t时可获得较好的脱硫效果。
基金Item Sponsored by National High Technology Research and Development Program(863 Program)of China(2007AA03Z548)Natural Science Foundation of Jiangsu Province of China(BK2010355)
文摘B2O3 is selected as fluxing agent of CaO-based ladle refining slag to decrease the melting temperature as well as to improve the speed of slag forming and the refining efficiency. The effects of B2O3 on the melting temperature of two series of refining slags including the low basicity slags （the mass ratio of CaO/SiO2 is 3--4） and the high basicity slags （the mass ratio of CaO/SiO2 is 5--8.75） were investigated. The slag melting temperature was meas- ured using the hemisphere method. The results indicate that the fluxing action of B2O3 is better than that of CaF2 and A1203. For the CaO-based refining slag with low basicity, the melting temperature is decreased effectively when B2O3 is used to substitute for equal mass of CaF2, Al2O3 and SiO2, respectively. For the CaO-based refining slag with high basicity, when CaF2 is substituted by B2 03, the melting temperature can be decreased remarkably. Espe- cially, when the mass ratios of CaO/Al2O3 and CaO/SiO2 are in the range of 1.1--4.0 and 5.25--8. 0, respectively, the slag melting temperature is lower than 1 300 ℃. Therefore, the 132 03-containing refining slags with high ratios of CaO/Al2O3 and CaO/SiO2 have ultra low melting temperature.
基金supported by the National Basic Research Program of China (Grant No. 2010CB630806)
文摘Investigations were made both in laboratorial and industrial scales on formation of non-metallic inclusions with relatively lower melting temperatures to improve the fatigue property of the special steels which contained extra low oxygen.It was found in laboratory studies that steel/slag reaction time largely affected non-metallic inclusions in steel.With the slag/steel reaction time increasing from 30 to 90 min,inclusions of MgO-Al2O3 spinel were gradually changed into CaO-MgO-Al2O3 system inclusions which were surrounded by lower melting temperature softer CaO-Al2O3 surface layers.By using high basicity and as much as 41 mass% Al2O3 refining slag,the ratio of the lower melting temperature CaO-MgO-Al2O3 system inclusions was remarkably increased to above 80%.In the industrial experiments,it was found that the inclusions changed in the order of "Al2O3 →MgO-Al2O3 system→CaO-MgO-Al2O3 system" in the secondary refining,and the change from MgO-Al2O3 system to CaO-MgO-Al2O3 system took place from the outside to the inside.The diffusion of CaO and MgO inside the layer of CaO-MgO-Al2O3 was considered as the controlling step of the inclusion transfer.Through LF and RH refining,most inclusions could be transferred to lower melting temperature CaO-Al2O3 and CaO-MgO-Al2O3 system inclusions.
