特厚板中碳低合金钢用结晶器保护渣的研制与应用
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摘要
特厚板中碳低合金钢的浇铸,因钢种中合金元素含量高,出现纵裂纹、横裂纹的缺陷率大,为降低缺陷率,通过优化连铸保护渣来解决当前存在的问题:1)为保证良好的控制传热效果,采取较高的碱度,控制二元碱度w(CaO)/w(SiO_2)在1.0~1.2,同时引入含MnO_2的材料进行着色;2)因拉速低,为防止深振痕产生,采用较高的黏度(1 300℃下0.2~0.3Pa·s);3)为保证良好的流动性及控制好合适的渣层结构,采取合理的配碳结构(2.5%炭黑+4%石墨),及合适的熔化温度(1 140~1 180℃);4)提高保护渣在使用过程的稳定性,防止变性,引入含B_2O_3、BaO类材料,同时采取混合基料。通过上述措施,成功研制出了满足特厚板中碳低合金钢浇铸的连铸保护渣,使铸坯裂纹缺陷率由之前的30%降低到1%以下。
Because of high content of alloying elements in steel,medium-carbon low-alloy steel of special thick slabs had large defect rates of longitudinal crack cracks and transverse cracks.To reduce the defect rates,the methods of optimizing mould slag were adopted.1)To ensure good control of heat transfer effect,a higher basicity was obtained by controlling the binary basicity w(CaO)/w(SiO_2)in 1.0-1.2,and the MnO_2-containing material was introduced for coloring.2)Because of low casting speed,high viscosity(0.2-0.3 Pa·s at 1 300 ℃)was used for preventing deep vibration marks.3)A reasonable carbon structure(2.5 %carbon black+4% Graphite)and appropriate melting temperature(1 140-1 180 ℃)were adopted to ensure good fluidity and control the proper slag layer structure.4)The stability of the mould slag was improved in order to prevent denaturation,through the B_2O_3 and BaO materials and mixed-base materials were taken.Through the implementation of these measures,the continuous casting mould slag used in medium-carbon low-alloy steel of special thick slabs had bseen successfully developed,the defect rate of slab cracks reduced from 30 %to less than 1 %.
Because of high content of alloying elements in steel,medium-carbon low-alloy steel of special thick slabs had large defect rates of longitudinal crack cracks and transverse cracks.To reduce the defect rates,the methods of optimizing mould slag were adopted.1)To ensure good control of heat transfer effect,a higher basicity was obtained by controlling the binary basicity w(CaO)/w(SiO_2)in 1.0-1.2,and the MnO_2-containing material was introduced for coloring.2)Because of low casting speed,high viscosity(0.2-0.3 Pa·s at 1 300 ℃)was used for preventing deep vibration marks.3)A reasonable carbon structure(2.5 %carbon black+4% Graphite)and appropriate melting temperature(1 140-1 180 ℃)were adopted to ensure good fluidity and control the proper slag layer structure.4)The stability of the mould slag was improved in order to prevent denaturation,through the B_2O_3 and BaO materials and mixed-base materials were taken.Through the implementation of these measures,the continuous casting mould slag used in medium-carbon low-alloy steel of special thick slabs had bseen successfully developed,the defect rate of slab cracks reduced from 30 %to less than 1 %.
引文
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[11]韩秀丽,姚明燕,刘磊,等.碱度对保护渣渣膜导热系数和结晶矿相的影响[J].河北联合大学学报,2015(7):43-46.
[2]迟景灏,甘永年.连铸保护渣[M].1版.沈阳:东北大学出版社,1998:5-6.
[3]朱志远,甄新刚,蒋海涛,等.400mm特厚板坯表面横裂纹控制技术[J].钢铁,2011(12):33-48.
[4]赵晶,王国连,秦登平,等.400mm特厚板坯尾坯表面横裂纹的控制[J].钢铁研究,2017,45(5):14-17.
[5]陈振业,张阔斌,王云阁,等.Q235B和Q345B钢中厚板表面纵裂纹的成因分析和工艺优化[J].特殊钢,2015(6):30-32.
[6]李彬,马鑫,贾睿乐,等.连铸板坯纵裂成因及控制措施分析[J].包钢科技,2015(6):46-49.
[7]彭其春,童志博,于学森,等.含硼中碳钢铸坯角部横裂纹影响因素分析[J].炼钢,2012,28(6):44-48.
[8]荒木泰泣.钢铁[M].2版.日本:青土社,1973:174-235.
[9]王南辉,谢兵.裂纹敏感性钢种连铸结晶器保护渣的研究现状[J].连铸,2006(5):39-42.
[10]潘红,吴国荣,曾建华,等.包晶钢用高碱度高润滑保护渣开发及应用实践[C]//第十八届全国炼钢学术会议论文集—S06:凝固与连铸,2014.
[11]韩秀丽,姚明燕,刘磊,等.碱度对保护渣渣膜导热系数和结晶矿相的影响[J].河北联合大学学报,2015(7):43-46.