Fe-Cr-Ni合金连铸坯皮下裂纹研究
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摘要
目前,Fe-Cr-Ni耐蚀合金连铸坯往往会产生皮下裂纹。为此,采用金相试验、电子探针分析和凝固过程的原位观察等方法,研究了150 mm厚×1 150 mm长的Fe-Cr-Ni合金连铸坯产生皮下裂纹的原因。试验结果表明,皮下裂纹大多发生在Fe-Cr-Ni合金连铸坯凝固前沿的晶界,该区域发现有大量的TiO_2、Al_2O_3等氧化物,这是Fe-Cr-Ni合金中Al和Ti元素与保护渣中的SiO_2反应的产物。此外,皮下裂纹内有钠和钾等元素,结晶器内化渣困难,弯月面处的保护渣易被卷入连铸坯皮下区域。Fe-Cr-Ni合金连铸坯的皮下裂纹主要是保护渣及其反应产物造成的。
At present, subsurface cracks often occur in continuously cast slab of corrosionresistant Fe-Cr-Ni alloy. For this fact,the reason why the subsurface cracks formed in a continuously cast Fe-Cr-Ni alloy slab 150 mm thick by 1 150 mm long was investigated with the use of metallographic examination,electron probe analysis,and in situ survey during the solidifying. The results showed that the subsurface cracks occurred largely in grain boundaries of the solidified Fe-CrNi alloy slab front where a large amount of oxides such as TiO_2 and Al_2O_3 which stemmed from reaction of Al and Ti present in Fe-Cr-Ni alloy with SiO_2 present in protecting slag were observed.Besides,elements such as sodium and potassium were present in the subsurface crack. The slagging was difficult to perform in the mould,and protecting slag lain in meniscus was easy to be drawn into the subsurface area. The subsurface cracks was mainly attributed to protecting slag and its reaction products.
At present, subsurface cracks often occur in continuously cast slab of corrosionresistant Fe-Cr-Ni alloy. For this fact,the reason why the subsurface cracks formed in a continuously cast Fe-Cr-Ni alloy slab 150 mm thick by 1 150 mm long was investigated with the use of metallographic examination,electron probe analysis,and in situ survey during the solidifying. The results showed that the subsurface cracks occurred largely in grain boundaries of the solidified Fe-CrNi alloy slab front where a large amount of oxides such as TiO_2 and Al_2O_3 which stemmed from reaction of Al and Ti present in Fe-Cr-Ni alloy with SiO_2 present in protecting slag were observed.Besides,elements such as sodium and potassium were present in the subsurface crack. The slagging was difficult to perform in the mould,and protecting slag lain in meniscus was easy to be drawn into the subsurface area. The subsurface cracks was mainly attributed to protecting slag and its reaction products.
引文
[1] HIDEKAZU T, TERUAKI I, KENJI M, et al. Effect of crystallization behavior of mold flux on slab surface quality of a Ti-bearing Fe-Cr-Ni super alloy cast by means of continuous casting process[J],Materials Science and Engineering A,2005,413(6):121-128.
[2]郭亮亮,徐正其,郑宏光,等. Fe-30Ni-20Cr合金连铸板坯纵裂的研究[J].宝钢技术,2011(4):79-82.
[3]高峰.连铸板坯皮下裂纹的产生原因分析[J].物理测试,2002(6):11-14.
[4] KAMETANI H. Fractal analysis of the surface cracks on continuously cast steel slabs[J]. Metallurgical and Materials Transactions B,1998,29(6):1261-1267.
[5] GRILL A,BRIMACOMBE J K,WEIBERG F. Mathematical analysis of stresses in continuous casting of steel[J].Ironmaking and Steelmaking,1976,3(1):38-47.
[6] NAKAMA K,HARUNA Y,NAKANO J,et al. The effect of alloy solidification path on sulfide formation in Fe-Cr-Ni alloys[J]. ISIJ International,2009,49(3):355-364.
[7] YUKI N,SHIBATA H,EMI T. Solubility of Mn S in Fe-Ni alloys as determined by in-situ observation of precipitation of Mn S with a confocal scanning laser microscope[J]. ISIJ International,1998,38(4):317-323.
[8]WON Y M,YEO T J,SEOL D J. A new criterion for internal crack formation in continuously cast steels[J]. Metallurgical and Materials Transactions B,2000,31(4):779-794.
[9]SUZUKI H G,NISHIMURA S,YAMAGUCHI S. Characteristics of hot ductility in steels subjected to the melting and solidification[J]. Transactions ISIJ,1982,22(1):48-56.
[10]MILLS K C,FOX A B. The role of mould fluxes in continuous casting-so simple yet so complex[J]. ISIJ International,2003,43(10):1479-1486.
[2]郭亮亮,徐正其,郑宏光,等. Fe-30Ni-20Cr合金连铸板坯纵裂的研究[J].宝钢技术,2011(4):79-82.
[3]高峰.连铸板坯皮下裂纹的产生原因分析[J].物理测试,2002(6):11-14.
[4] KAMETANI H. Fractal analysis of the surface cracks on continuously cast steel slabs[J]. Metallurgical and Materials Transactions B,1998,29(6):1261-1267.
[5] GRILL A,BRIMACOMBE J K,WEIBERG F. Mathematical analysis of stresses in continuous casting of steel[J].Ironmaking and Steelmaking,1976,3(1):38-47.
[6] NAKAMA K,HARUNA Y,NAKANO J,et al. The effect of alloy solidification path on sulfide formation in Fe-Cr-Ni alloys[J]. ISIJ International,2009,49(3):355-364.
[7] YUKI N,SHIBATA H,EMI T. Solubility of Mn S in Fe-Ni alloys as determined by in-situ observation of precipitation of Mn S with a confocal scanning laser microscope[J]. ISIJ International,1998,38(4):317-323.
[8]WON Y M,YEO T J,SEOL D J. A new criterion for internal crack formation in continuously cast steels[J]. Metallurgical and Materials Transactions B,2000,31(4):779-794.
[9]SUZUKI H G,NISHIMURA S,YAMAGUCHI S. Characteristics of hot ductility in steels subjected to the melting and solidification[J]. Transactions ISIJ,1982,22(1):48-56.
[10]MILLS K C,FOX A B. The role of mould fluxes in continuous casting-so simple yet so complex[J]. ISIJ International,2003,43(10):1479-1486.